Course Guide for HED 204

Course Information
Course Code: HED 204
Course Title: Communicable and Non communicable Diseases
Credit Unit: 2
Course Status: Core
Course Blub:
Semester: Second
Course Duration: One Semester
Required Hours for Study: 30
Course Team
Course Writer: Dr.Ahmad Makama Getso
Content Editor: Prof.O. A. Moronkola
Instructional Designer:
Learning Technologists:
Copy Editor
Ice Breaker
You have an information regarding diseases the one that can be transmitted from one person to
another and the one that cannot be transmitted from one person to another. You in your life you
have contracted with one disease or the other. Also, you have done some courses that may
introduce you to communicable and non-communicable diseases. Mention any four communicable
and non-communicable diseases.

Introduction
HED 204- communicable and non-communicable diseases. The course is a core course in second
semester. It will take you 15 weeks to complete the course. You are to spend 91 hours of study for
a period of 13 weeks while the first week is for orientation and last week is for end semester
examination. The credit earned in this course is part of the requirement for graduation.
You will receive the course material which you can read online or download and read off-line. The
online course material is integrated in the Learning Management System (LMS). All activities in
this course will be held in the LMS. All you need to know in this course is presented in the
following sub-headings.

Course Competencies
By the end of this course, you will gain competency:
 in having the knowledge, nature, causes of communicable diseases

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  in having the knowledge, nature, causes of non-communicable diseases
 to have better understanding of communicable and non-communicable diseases preventive
measures
 to have ability to educate community on preventive strategies of communicable and non-
communicable diseases
 to represent and reason with Knowledge

Course Objectives
The course objectives are to:
 Provide background information on communicable and non-communicable diseases
 Create awareness on the preventive measures of communicable and non-communicable
diseases
 Gain an overview of the various means of communicable and non-communicable disease
transmission

Working through this Course

The course is divided into modules and units. The modules are derived from the course
competencies and objectives. The competencies will guide you on the skills you will gain at the
end of this course. So, as you work through the course, reflect on the competencies to ensure
mastery. The units are components of the modules. Each unit is sub-divided into introduction,
intended learning outcome(s), main content, self-assessment exercise(s), conclusion, summary,
and further readings. The introduction introduces you to the unit topic. The intended learning
outcome(s) is the central point which help to measure your achievement or success in the course.
Therefore, study the intended learning outcome(s) before going to the main content and at the end
of the unit, revisit the intended learning outcome(s) to check if you have achieved the learning
outcomes. Work through the unit again if you have not attained the stated learning outcomes.

The main content is the body of knowledge in the unit. Self-assessment exercises are embedded in
the content which helps you to evaluate your mastery of the competencies. The conclusion gives
you the takeaway while the summary is a brief of the knowledge presented in the unit. The final
part is the further readings. This takes you to where you can read more on the knowledge or topic
presented in the unit. The modules and units are presented as follows:
Module 1: Overview of Disease
Unit 1 : Disease Causing Agents
Unit 2 : Importance of Disease Study
Unit 3: Factors Involved in the Transmission of Communicable Diseases
Unit 4: Risk Factors of Non-Communicable Diseases
Unit 5: Problem of Communicable Disease among School Age-group
Module 2: Communicable Diseases
Unit 1: Indirect contact (Water and Food bone)

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Hepatitis
Poliomyelitis
Unit 2 : Vector bone
Malaria
Onchocerciasis
Yellow fever
Unit 3: Direct contact
HIV/AIDS
Syphilis
Gonorrhoea
Unit 4
Tuberculosis
Rabies
Unit 5 Transmission process and Preventive Measures of communicable diseases
Module 3: Non-Communicable Diseases
Unit 1 : Cancer and Obesity
Unit 2 : Hypertension
Unit 3 : Diabetes
Unit 4 : Sickle cell Anaemia and Arthritis
Unit 5 : Prevention and Control of Non-Communicable Diseases
There are fifteen units in this course. Each unit represent a week of study.

Presentation Schedule
The weekly activities are presented in Table 1 while the required hours of study and the activities
are presented in Table 2. This will guide your study time. You may spend more time in completing
each module or unit.
Table I: Weekly Activities
Week Activity
1 Orientation and course guide
2 Module 1 Unit 1
3 Module 1 Unit 2
4 Module 1 Unit 3
5 Module 1 Unit 4 and 5
6 Module 2 Unit 1
7 Module 2 Unit 2
8 Module 2 Unit 3 and 4
9 Module 2 Unit 5
10 Module 3 Unit 1
11 Module 3 Unit 2
12 Module 3 Unit 3
13 Module 3 Units 4 and 5
14 Revision and response to questionnaire
15 Examination

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The activities in Table I include facilitation hours (synchronous and asynchronous), assignments,
mini projects, and laboratory practical. How do you know the hours to spend on each? A guide is
presented in Table 2.

Table 2: Required Minimum Hours of Study

S/N Activity Hour per Hour per
Week Semester
1 Synchronous Facilitation (Video Conferencing) 2 26
2 Asynchronous Facilitation (Read and respond to posts 4 52
including facilitator’s comment, self-study)
3 Assignments, mini-project, laboratory practical and 1 13
portfolios
Total 7 91

Assessment
Table 3 presents the mode you will be assessed.
Table 3: Assessment
S/N Method of Assessment Score (%)
1 Portfolios 10
2 First C.A Test 20
3 Second C.A Test 20
4 Assignments 10
5 Final Examination 40
Total 100

Portfolio
A portfolio has been created for you tagged “My Portfolio”. With the use of Microsoft Word, state
the knowledge you gained in every Module and in not more than three sentences explain how you
were able to apply the knowledge to solve problems or challenges in your context or how you
intend to apply the knowledge. Use this Table format:
Application of Knowledge Gained
Module Topic Knowledge Gained Application of Knowledge Gained

You may be required to present your portfolio to a constituted panel.

First C.A Test

You will be required to write first C.A test from the beginning to the middle of the semester for
the continuous assessment.

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Second C.A Test
You will be required to write the second C.A. test at the end of the semester for your continuous
assessment.

Assignments
Take the assignment and click on the submission button to submit. The assignment will be scored,
and you will receive a feedback.
Examination
Finally, the examination will help to test the cognitive domain. The test items will be mostly
application, and evaluation test items that will lead to creation of new knowledge/idea.

How to get the Most from the Course

To get the most in this course, you:
 Need a personal laptop. The use of mobile phone only may not give you the desirable
environment to work.
 Need regular and stable internet.
 Need to install the recommended software.
 Must work through the course step by step starting with the programme orientation.
 Must not plagiarise or impersonate. These are serious offences that could terminate your
studentship. Plagiarism check will be used to run all your submissions.
 Must do all the assessments following given instructions.
 Must create time daily to attend to your study.

Facilitation
There will be two forms of facilitation – synchronous and asynchronous. The synchronous will
be held through video conferencing according to weekly schedule. During the synchronous
facilitation:
 There will be two hours of online real time contact per week making a total of 26 hours for
thirteen weeks of study time.
 At the end of each video conferencing, the video will be uploaded for view at your pace.
 You are to read the course material and do other assignments as may be given before video
conferencing time.
 The facilitator will concentrate on main themes.
 The facilitator will take you through the course guide in the first lecture at the start date of
facilitation

For the asynchronous facilitation, your facilitator will:

 Present the theme for the week.

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  Direct and summarise forum discussions.
 Coordinate activities in the platform.
 Score and grade activities when need be.
 Support you to learn. In this regard personal mails may be sent.
 Send you videos and audio lectures, and podcasts if need be.
Read all the comments and notes of your facilitator especially on your assignments, participate in
forum discussions. This will give you opportunity to socialise with others in the course and build
your skill for teamwork. You can raise any challenge encountered during your study. To gain the
maximum benefit from course facilitation, prepare a list of questions before the synchronous
session. You will learn a lot from participating actively in the discussions.
Finally, respond to the questionnaire. This will help ACETEL to know your areas of challenges
and how to improve on them for the review of the course materials and lectures.

Learner Support
You will receive the following support:
 Technical Support: There will be contact number(s), email address and chat resources on
the Learning Management System where you can chat or send message to get assistance
and guidance any time during the course.

 24/7 communication: You can send personal mail to your facilitator and the centre at any
time of the day. You will receive answer to you mails within 24 hours. There is also
opportunity for personal or group chats at any time of the day with those that are online.

 You will receive guidance and feedback on your assessments, academic progress, and
receive help to resolve challenges facing your studies.

Course Development

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 HED 204: COMMUNICABLE AND NON-COMMUNICABLE DISEASES

BY

AHMAD MAKAMA GETSO

BAYERO UNIVERSITY KANO-NIGERIA
08060653114
makamagetso@gmail.com

EDITOR: PROF. O.A. MORONKOLA

UNIVERSITY OF IBADAN-NIGERIA
080823415695 walwmoronkola@yahoo.com

Contents
Module 1 Overview of Disease
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Unit 1 Disease Causing Agents
Unit 2 Importance of Disease Study
Unit 3 Factors Involved in the Transmission of Communicable Diseases
Unit 4 Risk Factors of Non-Communicable Diseases
Unit 5 Problem of Communicable Disease among School Age-group

Module 2 Communicable Diseases

Unit 1: Indirect contact (Water and Food bone)
Hepatitis
Poliomyelitis
Unit 2: Vector bone
Malaria
Onchocerciasis
Yellow fever
Unit 3: Direct contact
HIV/AIDS
Syphilis
Gonorrhoea
Unit 4:
Tuberculosis
Rabies
Unit 5: Transmission Process and Preventive Measures of Communicable Diseases

Module 3 Non-Communicable Diseases

Unit 1 cancer and Obesity
Unit 2 Hypertension
Unit 3 Diabetes
Unit 4 Sickle cell Anaemia and Arthritis
Unit 5 Prevention and Control of Non-Communicable Diseases

Module 1 Overview of Disease

Basic information on disease will be provided in this module to equip you with knowledge of
signs, symptoms, causes, and prevention and control measures. Having knowledge of diseases will
influence your attitude towards and practice of preventive measures of disease contraction. The
knowledge of disease will favourably influence your health seeking behaviour of students and
community.
Unit 1 Disease Causing Agents
Unit 2 Importance of Disease Study
Unit 3 Factors Involved in the Transmission of Communicable Diseases
Unit 4 Risk Factors of Non-Communicable Diseases
Unit 5 Problem of Communicable Disease among School Age-group
Unit 1 Communicable Diseases Causing Agents
CONTENTS
1.0 Introduction

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 2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Disease
3.2 Infectious Agents
3.3 Types of Infectious Agents
3.3.1 Bacterial infections
3.3.2 Fungal infections
3.3.3 Other infections
3.4 Causes of infection
3.5 Symptoms of infection
3.6 Prevention against infection
3.7 Prevention and control of disease
4.0 Self-Assessment
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

Communicable diseases constitute serious public health challenge in both developed and under
developed nations. Many died and others sustain different disabilities as a result of communicable
diseases. This is due to inadequate manpower and facilities to address the problem or in ability to
use appropriate preventive measures that will reduce the menace of communicable diseases
contraction more particularly in developing countries. In this unit you will learn the definition of
disease, prevention as well as control measures of communicable disease.

2.0 Intended Learning Outcome(ILOs)

By the end of this unit, you will be able to:

 define disease.
 identify different types of disease causing agents.
 describe the prevention and control measures of communicable diseases.

3.0 Main Content

3.1 Disease

Disease refers to any harmful deviation from the normal structural or functional state of an
organism, generally associated with certain signs and symptoms and differing in nature from
physical injury. A diseased organism commonly exhibits signs or symptoms indicative of its
abnormal state. Thus, the normal condition of an organism must be understood in order to
recognise the hallmarks of disease. Nevertheless, a sharp demarcation between disease and health
is not always apparent, (Scarpelli & Burrows, 2019). A disease may also be seen as a particular
abnormal condition that negatively affects the structure or function of part or all of an organism,

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and that is not due to any external injury, (Scarpelli & Burrows 2019). Diseases are often construed
as medical conditions that are associated with specific symptoms and signs. (Scarpelli&Burrows,
2019) A disease may be caused by external factors such as pathogens or by internal dysfunctions.
For example, internal dysfunctions of the immune system can produce a variety of different
diseases, including various forms of immunodeficiency, hypersensitivity, allergies and
autoimmune disorders.

3.2 Infectious Agents

These refer to organisms that are responsible for causing pathological changes in human, animals
or plants body due to its invasion .They are also known as disease causing organisms. The
organism uses a person's body to sustain itself, reproduce, and colonise. These infectious
organisms are known as pathogens. Examples of pathogens include bacteria, viruses and fungi
Pathogens can multiply and adapt quickly.

Some infections are mild and barely noticeable, but others are severe and life-threatening, and
some are resistant to treatment. Infection can be transmitted in a variety of ways.

These include skin contact, bodily fluids, contact with feces, airborne particles, and touching an
object that an infected person has also touched. How an infection spreads and its effect on the
human body depend on the type of agent.

The immune system is an effective barrier against infectious agents, but colonies of pathogens may
grow too large for the immune system to fight. At this stage, infections become harmful.
Many pathogens give off toxins that trigger negative responses from the body.

Basic facts on infection

 Infection is the effect of a foreign organism in the body.

 Types of infection include bacterial, fungal, viral, protozoan, parasitic, and prion disease.
 They are classified by the type of organism causing the infection.
 Infections can range from mild inflammation in one person to an epidemic.

3.3 Types of Infectious Agents

Bacteria are one type of infectious agent.

Bacteria, viruses, fungi, protozoa, parasites, and prions are different types of pathogen. They
vary in their size, shape, function, genetic content, and how they act on the body.

For example, viruses are smaller than bacteria, and they can enter a host and take over cells.
However, bacteria can survive without a host.

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Treatment will depend on the type of pathogen. This article will focus on the most common and
deadly types of infection: Bacterial, viral, fungal, and prion.

Viral infections

The common cold is a viral infection.

Viral infections are caused by virus and there are millions types of virus that are existing, but
only 5,000 types have been identified. Viruses contain a small piece of genetic code. They are
protected by a coat of protein and fat. Viruses invade a host and attach themselves to a cell. As
they enter the cell, they release genetic material. The genetic material forces the cell to replicate,
and the virus multiplies. When the cell dies, it releases new viruses, and these go on to infect new
cells.

Not all viruses destroy their host cell. Some of them change the function of the cell. In this way,
viruses such as human papillomavirus (HPV) or Epstein-Barr virus (EBV) can lead to cancer by
forcing cells to replicate in an uncontrolled way. They can also target certain age groups, such as
infants or young children. A virus may remain dormant for a period before multiplying again. The
person with the virus can appear to have recovered but may get sick again when the virus
reactivates.

Here are some examples of viral infections:

 the common cold, mainly caused by the rhinovirus, coronavirus, and adenovirus
 encephalitis and meningitis, caused by enteroviruses and the herpes viruses
 warts and skin infections, caused by the human papillomaviruses (HPV) and herpes
simplex virus (HSV).
 gastroenteritis, caused by the nova virus

Other viral conditions include:

 Zika virus
 human immunodeficiency virus (HIV)
 hepatitis C
 polio
 influenza
 Dengue fever
 H1N1 swine flu
 Ebola
 Middle East respiratory syndrome (MERS-CoV)

Antiviral medications help in some cases. They can either prevent the virus from reproducing or
boost the host's immune system. Antibiotics are not effective against viruses. Using antibiotics
against a virus will not stop the virus, and it increases the risk of antibiotic resistance.
Most treatment aims to relieve symptoms while the immune system combats the virus without
assistance from medicine.

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3.3.1 Bacterial infections

Bacteria are single-celled microorganisms known as prokaryotes. They are estimated to be at least
one million bacteria on the earth. Bacteria do exist in any of three main shapes:

 Spherical: These are usually the simplest to treat and are known as cocci.
 Rod-shaped: These are called bacilli.
 Spiral: Coiled bacteria are known as spirilla. If the coil of a spirillus is particularly tight,
they are known as spirochetes.

(Figure1.1) Bacteria

Bacteria can live in almost any kind of environment, from extreme heat to intense cold, and some
can even survive in radioactive waste. There are trillions of strains of bacteria, and few of these
cause diseases in humans. Some of them live inside the human body without causing harm, for
example in the gut or airways. Some "good" bacteria attack "bad" bacteria and prevent them from
causing sickness. However, some bacterial diseases are deadly. These include: cholera, diphtheria,
dysentery, bubonic plague, pneumonia, tuberculosis ,typhoid and typhus. Some examples of
bacterial infections are: bacterial meningitis, otitis media ,pneumonia ,tuberculosis ,upper
respiratory tract infection ,gastritis ,food poisoning ,eye infections ,sinusitis ,urinary tract
infections ,skin infections and sexually transmitted diseases. Bacterial infections can be treated
with antibiotics, but some strains become resistant and can survive the treatment.

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3.3.2 Fungal Infection
Fungi reproduce by spreading spores. A fungus is an often multi-cellular parasite that can
decompose and then absorb organic matter using an enzyme. They almost always reproduce
through the spreading of single-celled spores, and the structure of a fungus is normally long and
cylindrical with small filaments branching from the main body. This structure is known as hypha.
There are approximately 51 million species of fungus. Many fungal infections will appear in the
upper layers of the skin, and some progress to the deeper layers. Inhaled fungal spores can lead to
systemic fungal infections, such as thrush, or candidiasis. Systemic diseases affect the whole body.
The body usually has a population of "good" bacteria that help to maintain the balance of
microorganisms in the intestines, mouth, vagina, and other parts of the body.
Figure 2.2 Fungal infection

If enough "good" bacteria are destroyed, for example, by overusing antibiotics, fungi can grow
and cause health problems for the host. Those with a higher risk of developing a fungal infection
include people who: use strong antibiotics for a long time ,have a weakened immune system, due,
for example, to HIV or AIDS, diabetes, chemotherapy treatment, and those who have undergone
a transplant, as they take medications to prevent their body from rejecting the new organ.
Examples of fungal infections are: valley fever, or coccidioidomycosis, athlete's foot ringworm,
some eye infections. A rash can be an indicator of a fungal infection of the skin.

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Prion disease: A prion is a protein that contains no genetic material. It is normally harmless, but
if it folds into an abnormal shape, it can become a rogue agent and affect the structure of the brain
or other parts of the nervous system.

Prions do not replicate or feed on the host but trigger abnormal behaviour in the body cells
proteins.Prion diseases are rare, but they progress rapidly, and all are currently fatal. Prions cause
degenerative brain diseases, such as: bovine spongiform encephalopathy (BSE), also known as
mad cow disease, Creutzfeldt-Jakob disease (CJD)Researchers have linked some cases of
Alzheimer's disease to prion infection.

3.3.3 Other infections

While the forms of infection mentioned above are the main types, there are others that can have
an effect on the body. A single-celled organism with a nucleus can cause a protozoan infection.

Figure 3.3 Staph Infection (Staphylococcus Aureus)

Protozoa commonly show features similar to animals, such as mobility, and can survive outside of
the human body. They are most commonly transferred by contact with feces. When they enter the
human body, protozoa can also cause infection. Amebic dysentery is an example of a protozoan
infection.

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Helminths are larger, multicellular organisms that tend to be visible to the naked eye when full-
grown. This type of parasite includes flatworms and roundworms. These are also able to infect the
human body. Finally, ectoparasites such as mites, ticks, lice, and fleas can cause infection by
attaching or burrowing into the skin. The term can also include blood-sucking arthropods, such as
mosquitos, that transmit infection by consuming human blood.

3.4 Causes of Infection

The cause of an infection is said to be whichever type of organism has invaded the body. A
particular virus, for example, will be the cause of a viral infection. The effects of an infection, such
as swelling or a runny nose, occur as a result of the immune system fighting the invading organism.
A wound filling with pus, for example, occurs when white blood cells rush to the site of an injury
to combat foreign bacteria.

Symptoms of Infection

The symptoms of an infection depend on the organism responsible as well as the site of the
infection.

Viruses target specific cells, such as those in the genitals or upper respiratory tract. The rabies
virus, for example, targets the nervous system. Some viruses target skin cells, causing warts.
Others target a wider range of cells, leading to various symptoms. A flu virus can cause a runny
nose, muscle aches, and an upset stomach.

A person with a bacterial infection will often experience redness and heat, swelling, fever, pain at
the site of infection, and swollen lymph glands. A bacterial infection is less likely to affect a wide
area of the body than a viral one. A rash can be an indicator of a fungal infection of the skin.
Common symptoms of prion diseases an indicator of a fungal infection of the skin. Common
symptoms of prion diseases include brain damage, memory loss, and cognitive difficulties. They
can also trigger the buildup of plaque in the brain, causing it to waste away.

3.6 Prevention against Infection

There is no single way to prevent all infectious diseases, but the following tips can reduce the risk
of transmission:

 Wash your hands often, especially before and after preparing food and after using the
bathroom.
 Clean surface areas and avoid leaving room-temperature food exposed when cooking.
 Receive any recommended vaccinations, and keep them up to date.
 Only take antibiotics when prescribed, and be sure to complete any recommended course
even if symptoms improve earlier than anticipated.
 Disinfect rooms where there may be high concentrations of bacteria, such as the kitchen
and bathroom.
 Practice safe sex by receiving regular STIs checks, using condoms, or abstaining
altogether.

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  Avoid sharing personal items such a toothbrushes, combs, razor blades, drinking glasses,
and kitchen utensils.
 Follow a doctor's advice about travel ling or working when you are ill, as you could infect
others.

A healthy, active lifestyle can help keep the immune system strong and able to defend the body
against different kinds of infection (Nordqvist & Charles, 2017).

3.7 Prevention Control of Disease

Most diseases are preventable to a greater or lesser degree, the chief exceptions being the idiopathic
diseases, such as the inherited metabolic defects. In the case of those diseases resulting from
environmental exposures, prevention is a matter of eliminating, or sharply reducing, the factors
responsible in the environment. Because chemicals and other substances and materials originate
largely from human activities, prevention ought to be a simple matter of the application of well-
established principles of industrial hygiene. In practice, however, this is often difficult to achieve.

The infectious diseases may be prevented in one of two general ways:

1. By preventing contact, and therefore transmission of infection, between the susceptible host and
the source of infection and;
2. By rendering the host unsusceptible, either by selective breeding or by introduction of an
effective artificial immunity. The nature of the specific preventive measures and their efficacy,
varies from one disease to another.

Quarantine, which is an effective method of preventing transmission of disease in principle, has

had only limited success in actual practice. In only a few instances has quarantine achieved
prevention of the spread of disease across international borders, and quarantine of individual cases
of human disease has long been abandoned as ineffective, (Scarpelli&Burrows, 2019).

4.0 Self-Assessment Exercise

Explain what infectious agent of a disease is,

Outline any four (4) disease causing agents and give two (2) examples of disease caused by the
agent outlined.

5.0 Conclusion

Knowledge of disease facilitates better use of preventive measures against the spread of disease
among the students and community at large. It will also help clinicians to develop drugs for the
management of diseases, as well as public health officers to mount effective strategies of
prevention and control of diseases.

6.0 Summary

Disease is the invasion of pathogen into human body which has potential of causing pathological
changes. Different diseases are caused by different infectious agent such as; virus causes viral

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infection, bacteria causes bacterial infection, parasites causes parasitic infection, fungal causes
fungal infection, etc.

7.0 References/ Further Reading

Nordqvist, C. &Charles, M., (2017). Everything you need to Know about Infectious Agent
http://www.browardhealthservices.com/communicable-diseases/communicable-diseases-
prevention-and-control/

Scarpelli, D.G & Burrows , W.(2019). Science Museum - Brought To Life - Diseases and
epidemics. Chicago, IL, United States. Disease at Dorland's Medical Dictionary

Answer to Self-Assessment Exercise

This refers to an organism that is responsible for causing pathological changes in human, animals
or plants body due to its inversion. The organism use a person's body to sustain itself, reproduce,
and colonize. Infectious organisms are known as pathogens. Examples of pathogens include
bacteria, viruses, fungi, and prions. Pathogens can multiply and adapt quickly.

1. Two examples of diseases caused by bacteria

i. Cholera
ii. Diphtheria

2 Two examples of diseases caused by Virus are

i. Zika Virus
ii. Human Immunodeficiency Virus (HIV)
3. Two examples of diseases caused by Fungi
i. Valley fever
ii. Athlete’s foot

4. Two examples of diseases caused by Prions

i. Bovine spongiform encephalopathy (BSE), also known as mad cow disease

ii. Creutzfeldt-Jakob disease (CJD)

Unit 2: Importance of Disease Study

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Importance of Disease Study
4.0 Self-Assessment Exercise
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

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1.0 Introduction

In the previous unit you have learnt definition of disease, prevention and control measures of
communicable disease. In this unit you will learn the importance of disease study

2.0 Intended Learning Outcome (ILOs)

By the end of this unit, you will be able to:

 enumerate the importance of studying diseases.
 apply the importance of studying disease.

3.0 Main Content

3.1 Importance of Disease Study

Global health research should not only generate knowledge. More importantly, it should lead to
action. In particular, research outcomes must guide policy and programme development as well as
the delivery of health services. Healthcare interventions should be evidence-based and grounded
in solid research.

Pneumonia, diarrheal diseases, tuberculosis and malaria, when combined, have been estimated to
account for more than 20% of the disease burden in the world (mostly in developing countries),
yet only 10% of the world expenditure on health research and development is spent on health
conditions that represent 90% of the global disease burden (Delisle, Roberts, Munro, Jones, &
Gyorkos, 2009). Having knowledge of disease causes, signs and symptoms and preventive
measures will make people to be aware of the action to be taken at the right time.

According to Health Encyclopaedia of the University of Rochester Medical Centre, New York,
clinical pathology covers a wide range of laboratory functions and is concerned with the diagnosis,
treatment, and prevention of diseases (Gundu, 2018). For instance, if we look at the studies related
to cardio-metabolic diseases, Framingham studies started over half a century ago discovered,
major risk factors associated with this cluster of diseases. Western medicine, which is considered
disease-centric developed guidelines to reduce or prevent these risks in the general populations.
Disease study can play significant role in educating people on cardiovascular and metabolic
diseases which could drastically reduce the complications and mortality rate from the diseases.

Cohn (20003), a pioneering cardiologist from the University of Minnesota has advocated that when
addressing a complex disease like ischemic heart disease, it is better to treat the disease rather than
just the risk factors. Atherosclerosis is a progressive disease of the vessel walls induced by
endothelial dysfunction and vascular pathology. This kind of philosophy was developed based on
extensive research in this area which traced progression of the vessel-wall disease to the current
state of knowledge (Ferrante, 2015). Disease study is important in disseminating of information
on prevention and control measures of diseases and health conditions which could reduce the
opportunistic infection.

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According to Gundu (2018), on-going studies from the Indian researchers as well as the
epidemiology group from the University of Southampton, the UK, have demonstrated that children
with low birth weight are pre-disposed to develop excess weight, obesity and cardio-metabolic
diseases. Large number of children are born with low birth weight in India (>30%) and China.
Robert Freishtat and associates at the children’s hospital. Basic observational studies by the
pediatrists at the Children’s hospital at Mysore, led to the discovery of relationship between low
birth weight and excess metabolic diseases. Now the studies by the Children’s hospital Washington
DC are trying to address the basic mechanism underlying obesity and metabolic diseases at the
cellular level (Ferrante, 2015). Disease study can be used to educate mothers’ of under-five on the
causes of low birth weight babies, abortion, birth complications as well as means of reducing the
rate maternal mortality.

Robert Freishtat and associates at the children’s hospital, Washington on DC, have hypothesized
that adipocyte-derived exosomes contain mediators capable of activating end-organ end-organ
inflammatory and fibrotic signaling pathways. These studies have become a part of bilateral
investigations between India and the US. These studies could soon become a game changer for
early detection and prevention of obesity-related cardio-metabolic diseases (Cohn, 20003).
Disease study provides necessary information on the importance of periodic medical check-up.
Which help in early detection of health problems for timely addressing.

These observations suggest that understanding the mechanisms of disease will provide the better
chance to develop personalised preventive measures. The world now is crowded and
interconnected planet, with a projected global human population of at least 9 billion by 2050.
Public health advances such as safe water, adequate sanitation, antibiotics, vaccines and balance.
Nutrition programs have extended overall life expectancy, even in remote, under-developed
settings. The resulting unprecedented population urge has contributed to numerous challenges that
will increasingly serve as counter-balances to these public health advances and will synergise with
other inter-related factors such globalisation, climate change and urbanization to contribute to the
spread of dangerous infectious diseases. However disease study is one of the strategy of addressing
this issue.

International travel and immigration increase each year, with more than 1 billion humans crossing
international borders in 2013 alone (UNWTO Annual Report 2014, June 2015). Many cross to
embrace economic opportunities or to escape war or disaster. Many also travel to visit family or
friends, or for business, education or leisure purposes. Exotic, remote and dangerous locations—
often lacking public health infrastructure—are increasingly common destinations for travelers as
well as sources of immigrants to the developed world. This “smaller world” effect brings with it
much good in terms of societal connectedness and economic stimulation, but also individual risk
to the traveler and the opportunity for spread of disease upon return.

Disease study is an important mechanism of stopping the spread and breaking the chain of disease
transmission which could occur as a result of international travel and tours or at local level. The
current globalisation also involves the increasingly rapid and direct transportation of food and
other products that can introduce or facilitate disease transmission, whether it be cyclosporiasis
associated with Latin America raspberries, (Bern , Hernandez , Lopez , Arrowood , DeMerick ,
Klein,1999 ) enterohemorrhagic E. coli infection associated with Middle Eastern fenugreek

19
sprouts, (Frank , Werber , Cramer , Askar , Faber , an der Heiden 2011),monkeypox from pet
Gambian rats and prairie dogs, (Reed, Melski , Graham, Regnery , Sotir , Wegner, 2004l) or
introduction into the US of Aedesalbopictus (the Asian Tiger mosquito and potential vector of
dengue and chikungunya) via imported used-tires from Asia (Vega-Rúa , Lourenço-de-Oliveira ,
Mousson , Vazeille,2015). Disease study provides desired information on food bone diseases and
possible way of reducing the menace of such diseases.

4.0 Self-Assessment Exercise

1. Outline the factors that could decrease the level of disease spread worldwide.

2. Briefly state the importance of studying disease.

5.0 Conclusion

Numerous factors contribute to the decrease of disease spread. It is quite imperative to have good
information about these factors in order to decrease the spread which in turns promote healthy
living among human population.

6.0 Summary

Having information about disease is the first giant step towards management and control of the
spread. It will also, help public health advances such as safe water, adequate sanitation, antibiotics,
vaccines and balance. Nutrition programs have extended overall life expectancy, even in remote,
under-developed settings.

7.0 References/ Further Reading

Bern C, Hernandez B, Lopez MB, Arrowood MJ, DeMerick AM, Klein RE.(1999). Epidemiologic
studies of Cyclosporacayetanensis in Guatemala. Emerg Infect Dis.;
PubMedViewArticleGoogle Scholar 5(6):766–74

Cohn JN, Hoke L, Whitwam W, Sommers PA, Taylor AL. (2003). Screening for early detection
of cardiovascular disease in asymptomatic individuals. Am Heart J 146(4): 679-685.

Delisle, Helene, Janet Hatcher Roberts, Michelle Munro, Lori Jones, and Theresa W Gyorkos.
"Health Research Policy and Systems." 21 Feb 2005 Web.25 Jun 2009.

Ferrante SC, Nadler EP, Pillai DK, Hubal MJ, Wang Z. (2015). Adipocyte-derived
exosomalmiRNAs: a novel mechanism for obesity-related disease. Pediatr Res 77(3): 447-
454.

Frank C, Werber D, Cramer JP, Askar M, Faber M, an der Heiden M, et al. Epidemic profile of
Shiga-toxin-producing Escherichia coli O104:H4 outbreak in Germany. N Engl J Med.
2011;365(19):1771–80.PubMedView ArticleGoogle Scholar

20
Gerland P, Raftery AE, Seveikova H, Li N, Gu D, Spoorenberg T, et al. World Population
Stabilization Unlikely this Century. Science. 2014;346(6206):234–7.Google Scholar

Gundu HR. (2018). Importance of Studying Disease and Disease Processes Journal of Laboratory
Medicine and Pathology, University of Minnesota, USA, Crimson publishers, Twin Cities;
155 (6): 1-6.
Research!America. (2007). America speaks: Poll summary. Alexandria, VA: United Health
Foundation; 7 (1): 56-60

Reed KD, Melski JW, Graham MB, Regnery RL, Sotir MJ, Wegner MV, et al. The detection of
monkeypox in humans in the Western Hemisphere. N Engl J Med. 2004;50(4):342–50.View
ArticleGoogle Scholar

UNWTO Annual report 2014, Jine 2015.http://dtxtq4w60xqpw.cloudfront.net/sites/all/files/pdf/u

nwto_annual_report_2014.pdf Accessed 11June2015.

Vega-Rúa A, Lourenço-de-Oliveira R, Mousson L, Vazeille M, et al. Chikungunya virus

transmission potential by local aedes mosquitoes in the americas and europe. PLoSNegl
Trop Dis. 2015;9(5):e0003780.PubMed CentralPubMedViewArticleGoogle Scholar

Westin A. (2008). How the public views privacy and health research. 2007. [accessed May 29,
2019].http://www.iom.edu/Object.File/Master/48/528/%20Westin%20IOM
%20Srvy%20Rept%2011-1107.pdf

Woolley M, Propst SM. (2005). Public attitudes and perceptions about health-related research.
JAMA; 294(11):1380–1384.
Answer to Self-Assessment Exercise

Q1. Having knowledge of disease causes, signs and symptoms and preventive measures will make
people to be aware of the action to be taken at the right time.

Disease study can play significant role in educating people on cardiovascular and metabolic
diseases which could drastically reduce the complications and mortality rate from the diseases.

Disease study is important in disseminating of information on prevention and control measures of

diseases and health conditions which could reduce the opportunistic infection.

Disease study can be used to educate mothers’ of under-five on the causes of low birth weight
babies, abortion, birth complications as well as means of reducing the rate of maternal mortality.

These observations suggest that understanding the mechanisms of disease will provide the better
chance to develop personalised preventive measures.

Disease study is an important mechanism of stopping the spread and breaking the chain of disease
transmission which could occur as a result of international travel and tours or at local level.

21
Disease study provides desired information on food bone diseases and possible way of reducing
the menace of such diseases.

Unit 3: Factors Involved in the Transmission of Communicable Diseases

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Communicable Diseases
3.2 Factors Involved in the Transmission of Communicable Diseases
3.3 Infectious Agents
3.4 Reservoirs of Infectious Agents
3.5 Route of Exit
3.6 Respiratory Track
3.7 Modes of Transmission
3.7.1 Route of Entry
3.7.2 Susceptible Hosts and Risk Factors
4.0 Self-Assessment Exercise
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

22
Many events happen time upon time for disease to be transmitted from one person to another or
from animal to human. The infectious agents causing disease gets into the body of an individual
and cause changes in the state of the health of that person. It could be through mouth, nose, eye,
skin and anus. Improving personal hygiene will help in breaking the chain of disease transmission.

2.0 Intended Learning Outcome (ILOs)

By the end of this unit, you will be able to:
 identify the factors involve in disease transmission.
 determine susceptible hosts and risk factors of disease infection.

3.0 Main Content

3.1 Communicable Diseases

Communicable diseases is an illnesses caused by viruses or bacteria that people spread to one
another through contact with contaminated surfaces, bodily fluids, blood products, insect bites, or
through the air (Edemekong& Huang,2019). There are many examples of communicable diseases,
some of which require reporting to appropriate health departments or government agencies in the
locality of the outbreak. Some examples of the communicable disease include HIV/AIDS, hepatitis
A, B and C, measles (Rubeola), salmonella, Cholera, Diphtheria, Plague, Rabies, Syphilis,
Tuberculosis and other blood-borne illnesses. Most common forms of spread include fecal-oral,
food, sexual intercourse, insect bites, contact with contaminated fomites, droplets, or skin contact
(Barrett, 1988).

3.2 Factors involved in the Transmission of Communicable Diseases

Transmission is a process in which several events happen one after the other in the form of a
chain. Hence, this process is known as a chain of transmission (figure below). Six major factors
can be identified: the infectious agent, the reservoir, the route of exit, the mode of transmission,
the route of entry and the susceptible host. Each of these factors will be discussed.

23
Fig.1.4: Factors involved in the Chain of Communicable Disease Transmission.
(Source: Nordqvist, & Charles, 2017).
For more information follow this Link
https://moodle.digitalcampus.org/mod/page/view.php?id=11608

3.3 Infectious Agents

Infectious agents can have varying sizes. Some, such as Plasmodium falciparum and all bacteria
and viruses, are tiny and are called micro-organisms, because they can only be seen with the aid
of microscopes. Others, such as the ascaris worm (Ascarislumbricoides), can be easily seen with
the naked eye.

Different types of infectious agents: their number of cells, visibility and examples. (Adapted
from the Open University, 2007, Water and Health in an Overcrowded World, Chapter 2)
Type of
Number
infectious Visibility Examples
of cells
agent

24
 Ascaris worm
causes ascariasis
Helminths Many Visible with the naked eye
Its length reaches
15–30 cm

Plasmodium
Visible with a standard
Protozoa 1 falciparum causes
microscope
malaria

Visible only with a special

Vibrio cholerae
Bacteria 1 microscope; much smaller
causes cholera
in size than protozoa

Visible only with a special

Viruses 0 microscope; much smaller HIV causes AIDS
in size than bacteria

Helminths are worms made up of many cells; for example, Ascarislumbricoides.

Protozoa are micro-organisms made up of one cell; for example, Plasmodium falciparum.

Bacteria are also micro-organisms made up of one cell, but they are much smaller than protozoa
and have a different structure; for example Vibrio cholerae, which causes cholera.

Viruses are infectious agents that do not have the structure of a cell. They are more like tiny boxes
or particles and are much smaller than bacteria; for example, HIV (the Human Immunodeficiency
Virus), which can lead to AIDS.

Though not as common as causes of communicable disease in humans, other types of infectious
agents include fungi (e.g. ringworm is caused by a fungus infection), and mites (similar to insects),
which cause scabies.

3.4 Reservoirs of Infectious Agents

Many infectious agents can survive in different organisms, or on non-living objects, or in the
environment. Some can only persist and multiply inside human beings, whereas others can survive
in other animals, or for example in soil or water. The place where the infectious agent is normally
present before infecting a new human is called a reservoir. Without reservoirs, infectious agents
could not survive and hence could not be transmitted to other people. Humans and animals which
serve as reservoirs for infectious agents are known as infected hosts. Two examples are people
infected with HIV and with the bacteria that cause tuberculosis; these infectious agents persist and
multiply in the infected hosts and can be directly transmitted to new hosts.

25
Animals can also be reservoirs for the infectious agents of some communicable diseases. For
example, dogs are a reservoir for the virus that causes rabies (Figure 1.3). Diseases such as rabies,
where the infectious agents can be transmitted from animal hosts to susceptible humans, are called
zoonoses (singular, zoonosis).

3.5 Route of Exit

Before an infectious agent can be transmitted to other people, it must first get out of the infected
host. The site on the infected host through which the infectious agent gets out is called the route
of exit. Some common examples are described below.

3.6 Respiratory Tract

The routes of exit from the respiratory tract are the nose and the mouth. Some infectious agents
get out of the infected host in droplets expelled during coughing, sneezing, spitting or talking, and
then get transmitted to others (Figure 1.4). For example, people with tuberculosis in their lungs
usually have a persistent cough; Mycobacterium tuberculosis uses this as its route of exit.

3.7 Modes of Transmission

Once an infectious agent leaves a reservoir, it must get transmitted to a new host if it is to multiply
and cause disease. The route by which an infectious agent is transmitted from a reservoir to another
host is called the mode of transmission. It is important for you to identify different modes of
transmission, because prevention and control measures differ depending on the type of infection.

3.7.1 Route of Entry

Successful transmission of the infectious agent requires it to enter the host through a specific part
of the body before it can cause disease. The site through which an infectious agent enters the host
is called the route of entry. It includes mouth, nose, eye, genital parts and skin.

3.7.2 Susceptible Hosts and Risk Factors

After an infectious agent gets inside the body it has to multiply in order to cause the disease. In
some hosts, infection leads to the disease developing, but in others it does not. Individuals who are
likely to develop a communicable disease after exposure to the infectious agents are called
susceptible hosts. Different individuals are not equally susceptible to infection, for a variety of
reasons.

Factors that increase the susceptibility of a host to the development of a communicable disease are
called risk factors. Some risk factors arise from outside the individual – for example, poor personal
hygiene, or poor control of reservoirs of infection in the environment. Factors such as these
increase the exposure of susceptible hosts to infectious agents, which makes the disease more
likely to develop.

4.0 Self-Assessment Exercise

1a. Explain the transmission process

1b. Draw the chain of communicable disease transmission.

26
Answer to Self-Assessment Exercise

1a. Transmission is a process in which several events happen one after the other in the form of a
chain. Hence, this process is known as a chain of transmission (figure below). Six major factors
can be identified: the infectious agent, the reservoir, the route of exit, the mode of transmission,
the route of entry and the susceptible host.

1b.Factors involved in the chain of communicable disease transmission.

5.0 Conclusion

Disease agents get into human body through route of entries which allow the agents to replicate
and overcome the immunity of the body resulted to pathological changes. Breaking this chain of
transmission will stop disease development and progression.

6.0 Summary
Factors that increase the susceptibility of a host to the development of a communicable disease
are called risk factors. Some risk factors arise from outside the individual such as, poor personal
hygiene, or poor control of reservoirs of infection in the environment. Factors such as these
increase the exposure of susceptible hosts to infectious agents, which makes the disease more
likely to develop

27
7.0 References/Further Readings

Barrett T. (1988). Infection Control Guidelines for Home Health Care. In: Abrutyn, Goldmann,
&Scheckler, eds. Saunders Infection Control Reference Service. Philadelphia, PA: WB
Saunders Company: 81-85.

Edemekong, PF&Huang, B. (2019).Epidemiology of Prevention of Communicable

Diseases.StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 3-5.

https://www.open.edu/openlearncreate/mod/oucontent/view.php?id=84&printable=1.( 2019).

Nordqvist, C., Charles, M., (2017). Everything you need to Know about Infectious Agent

http://www.browardhealthservices.com/communicable-diseases/communicable-diseases-
prevention-and-control/

Unit 4: Risk Factors of Non-communicable Diseases

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content

28
 3.1 Risk Factors of Communicable Diseases
3.2 Who is at risk of such Diseases?
3.3 Risk Factors of Non-Communicable Diseases
3.3.1 Modifiable Behavioural Risk Factor
3.3.2 Metabolic Risk Factor
3.4 What are the Socio-economic Impacts of NCDs?
4.0 Self-Assessment Exercise
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

Non-communicable diseases generally are long-lasting and progress slowly, and thus sometimes
also referred to as chronic diseases. They can arise from environmental exposures or from
genetically determined abnormalities, noticed during or after delivery or which may become
apparent later in life. These diseases include; metabolic diseases, cardiovascular diseases,
respiratory diseases and cancer. There are many risk factors that contribute to their emergence but
adhering to preventive measures will help in preventing their occurrences and their severity.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:

 distinguish the modifiable behavioural risk factors and metabolic modifiable risk factors.
 explain the relationship of socioeconomic status and non-communicable diseases.

3.0 Main Content

3.1 Risk Factors of Communicable Diseases

The World Health Organization (WHO) has identified four major types of non-communicable
disease: cancer, cardiovascular disease (e.g., heart attack, stroke), chronic respiratory disease (e.g.,
asthma), and diabetes mellitus. WHO estimated that, combined, these four groups of conditions
account for 82 percent of all deaths from non-communicable diseases. (Scarpelli & Burrows,
2019).

Non-communicable diseases (NCDs), also known as chronic diseases, tend to be of long duration
and are the result of a combination of genetic, physiological, environmental and behaviours
factors.

The main types of NCDs are cardiovascular diseases (like heart attacks and stroke), cancers,
chronic respiratory diseases (such as chronic obstructive pulmonary disease and asthma) and
diabetes.

NCDs disproportionately affect people in low- and middle-income countries where more than
three quarters of global NCD deaths – 32million – occur.

29
3.2 Who is at Risk of such Diseases?

People of all age groups, regions and countries are affected by NCDs. These conditions are often
associated with older age groups, but evidence shows that 15 million of all deaths attributed to
NCDs occur between the ages of 30 and 69 years. Of these "premature" deaths, over 85% are
estimated to occur in low- and middle-income countries. Children, adults and the elderly are all
vulnerable to the risk factors contributing to NCDs, whether from unhealthy diets, physical
inactivity and exposure to tobacco smoke or the harmful use of alcohol.

These diseases are driven by forces that include rapid unplanned urbanisation, globalization of
unhealthy lifestyles and population ageing. Unhealthy diets and a lack of physical activity may
show up in people as raised blood pressure, increased blood glucose, elevated blood lipids and
obesity. These are called metabolic risk factors that can lead to cardiovascular disease, the leading
NCD in terms of premature deaths.

3.3 Risk Factors of Non- Communicable Diseases

3.3.1 Modifiable Behavioural Risk Factors

Modifiable behaviours, such as tobacco use, physical inactivity, unhealthy diet and the harmful
use of alcohol, all increase the risk of NCDs.

 Tobacco accounts for over 7.2 million deaths every year (including from the effects of
exposure to second-hand smoke), and is projected to increase markedly over the coming
years.
 4.1 million annual deaths have been attributed to excess salt/sodium intake.
 More than half of the 3.3 million annual deaths attributable to alcohol use are from NCDs,
including cancer.
 1.6 million deaths annually can be attributed to insufficient physical activity.

3.3.2 Metabolic Risk Factors

Metabolic risk factors contribute to four key metabolic changes that increase the risk of NCDs:

 raised blood pressure

 overweight/obesity
 hyperglycemia (high blood glucose levels) and
 hyperlipidemia (high levels of fat in the blood).

In terms of attributable deaths, the leading metabolic risk factor globally is elevated blood pressure
(to which 19% of global deaths are attributed), followed by overweight and obesity and raised
blood glucose.

3.4 What are the Socioeconomic Impacts of NCDs?

30
NCDs threaten progress towards the 2030 Agenda for Sustainable Development, which includes a
target of reducing premature deaths from NCDs by one-third by 2030.

Poverty is closely linked with NCDs. The rapid rise in NCDs is predicted to impede poverty
reduction initiatives in low-income countries, particularly by increasing household costs
associated with health care. Vulnerable and socially disadvantaged people get sicker and die
sooner than people of higher social positions, especially because they are at greater risk of being
exposed to harmful products, such as tobacco, or unhealthy dietary practices, and have limited
access to health services.

In low-resource settings, health-care costs for NCDs quickly drain household resources. The
exorbitant costs of NCDs, including often lengthy and expensive treatment and loss of
breadwinners, force millions of people into poverty annually and stifle development (WHO, 2012-
2020). For more information follow this link: https://www.who.int/news-room/fact-
sheets/detail/noncommunicable-diseases.

4.0 Self-Assessment Exercise

1. Mention the types of non-communicable diseases as identified by World Health Organisation.
2. What are the behavioural modifiable risk factors and metabolic modifiable risk factors?

Answers to Self-Assessment Exercise

1. Four major types of non-communicable disease identified by WHO are: cancer, cardiovascular
disease (e.g., heart attack, stroke), chronic respiratory disease (e.g., asthma), and diabetes mellitus.
WHO estimated that, combined, these four groups of conditions account for 82% of all deaths
from non-communicable diseases.

2. Modifiable behavioural risk factors

Modifiable behaviours, such as tobacco use, physical inactivity, unhealthy diet and the harmful
use of alcohol, all increase the risk of NCDs.

 Tobacco accounts for over 7.2 million deaths every year (including from the effects of
exposure to second-hand smoke), and is projected to increase markedly over the coming
years.
 4.1 million annual deaths have been attributed to excess salt/sodium intake.
 More than half of the 3.3 million annual deaths attributable to alcohol use are from NCDs,
including cancer.
 1.6 million deaths annually can be attributed to insufficient physical activity.

Metabolic risk factors

Metabolic risk factors contribute to four key metabolic changes that increase the risk of NCDs:

 raised blood pressure

31
  overweight/obesity
 hyperglycemia (high blood glucose levels) and
 hyperlipidemia (high levels of fat in the blood).

5.0 Conclusion

Non-communicable diseases are those diseases that are claiming lives of many people. Also, these
diseases are called chronic diseases and are associated with poverty. The rapid rise in NCDs is
predicted to impede poverty reduction initiatives in low-income countries, particularly by
increasing household costs associated with health care. Vulnerable and socially disadvantaged
people get sicker and die sooner than people of higher social positions, especially because they are
at greater risk of being exposed to harmful products, such as tobacco, or unhealthy dietary
practices, and have limited access to health services.

6.0 Summary

Non- communicable diseases emergence depends on the risk factors an individual exposure.The
main types of NCDs are cardiovascular diseases (like heart attacks and stroke), cancers, chronic
respiratory diseases (such as chronic obstructive pulmonary disease and asthma) and diabetes.
NCDs disproportionately affect people in low- and middle-income countries where more than
three quarters of global NCD deaths – 32million – occur.

7.0 References/ Further Readings

Scarpelli, D.G& Burrows, W. (2019). Science Museum - Brought To Life - Diseases and
epidemics. Chicago, IL, United States. Disease at Dorland's Medical Dictionary

WHO developed a Global action plan for the prevention and control of NCDs 2013-2020, which
includes nine global targets that have the greatest impact on global NCD mortality. These
targets address prevention and management of NCDs.https://www.who.int/news-room/fact-
sheets/detail/noncommunicable-diseases

Unit 5: Communicable Diseases Related Problems

CONTENTS
3.0 Introduction
4.0 Intended Learning Outcomes (ILOs)

32
3.0 Main Content
3.1 Communicable Diseases Related Problems
3.1.1 Faecal-Oral
3.1.2 Respiratory
3.1.3 Direct Skin to Skin Contact
3.1.4 Indirect Contact
3.1.5 Blood Born
3.2 Problems of Communicable Diseases among School Age
4.0 Self-Assessment Exercise
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

Communicable diseases pose a serious challenge among children and adults in our communities.
Poor hand hygiene and failure to observe sanitation principles contribute immensely to emergence
of communicable diseases in schools. When schools and communities do not have health facilities
and the right services to address the cases of communicable diseases at an early stage and fail to
report illness to the appropriate authorities, such as public health specialists to assist schools and
communities in treating the situation, the case could be serious and out of school control. School
and communities authorities as well as students and community members need to have general
information on steps to be taken to prevent and control communicable diseases.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able:
 mention common routes of communicable diseases transmission.
 identify the steps to be taken in hand washing.
 mention the problems associated with communicable diseases.

3.0 Main Content

3.1 Communicable Diseases Related Problems
Understanding how diseases are spread can help prevent problems that result to illness. Here are
the most common routes of transmission:
3.1.1 Faecal-Oral
Contact with human stool; usually ingestion after contact with contaminated food or objects.
Viruses, bacteria, fungi, and parasites spread from person to person, sometimes causing diseases
as they move in and out of people's bodies along various routes. When the disease spreads through
the faecal-oral route, it means that contaminated faeces from an infected person are somehow
ingested by another person. For obvious reasons, this almost never happens deliberately. Usually,
the situation occurs when an infected person might forget to properly wash his hands after using

33
the toilet. Anything he or she touches afterward might be contaminated with microscopic germs
that other people may encounter.

Fig. 1.5: (Hand washing is your best defence)

Causes of Faecal Oral Transmission

While poor hand washing is a major cause of faecal-oral contamination, there are other equally
important considerations. Below are other ways microbes use the faecal-oral route to cause
disease:

 Drinking water contaminated with raw sewage.

 Eating shellfish (such as oysters and clams) that have been harvested from contaminated
water.
 Eating raw fruits or vegetables washed in contaminated water.
 Sexual activity that allows direct mouth-to-anus contact or indirect contact (touching the
mouth to something that touched the anus).
 Swimming pools that aren't properly disinfected.

Prevention
Good hand washing is a tremendously effective way to break the faecal-oral cycle. Other important
tools for preventing the spread of disease through faecal-oral transmission include:
 Using instant hand sanitizers when soap and water are not available.
 Practicing safe and careful food-handling practices.
 Avoiding ingestion of water in pools or from other non-potable sources.
 Using disposable towels.
 Cleaning or disinfecting commonly touched, infected surfaces such as doorknobs, faucet
handles, remote controls, etc.

3.1.2 Respiratory

34
Contact with respiratory particles or droplets from the nose, throat and mouth. Asthma is a chronic
inflammatory disorder of the airways characterized by episodes of reversible breathing problems
due to airway narrowing and obstruction. These episodes can range in severity from mild to life
threatening. Symptoms of asthma include wheezing, coughing, chest tightness, and shortness of
breath. Daily preventive treatment can prevent symptoms and attacks and enable individuals who
have asthma to lead active lives.

Risk factors for asthma currently being investigated include:

 Having a parent with asthma

 Sensitization to irritants and allergens
 Respiratory infections in childhood
 Overweight

Asthma affects people of every race, sex, and age. However, significant disparities in asthma
morbidity and mortality exist, particularly for low-income and minority populations. Populations
with higher rates of asthma include:

 Children
 Women (among adults) and boys (among children)
 African Americans
 Puerto Ricans
 People living in the northeastern United States
 People living below the federal poverty level
 Employees with certain exposures in the workplace

COPD is a preventable and treatable disease characterized by airflow limitation that is not fully
reversible. The airflow limitation is usually progressive and associated with an abnormal
inflammatory response of the lungs to noxious particles or gases (typically from exposure to
cigarette smoke).4 Treatment can lessen symptoms and improve quality of life for those with
COPD.

 Contact with infected skin Impetigo – This infection is spread by contact with the sores of
an infected person and most often affects infants and children.
 Molluscum contagiosum – This virus spreads to other body parts by scratching or from
person to person. In adults, molluscum contagiosum is often acquired through sexual
contact.
 Fungal infections – People get fungal infections from breathing in or brushing up against
fungal spores in the environment. Most often they affect people with weakened immune
systems.
 Athlete’s foot – The fungus that causes athlete’s foot is often found on damp surfaces such
as around a swimming pool or public showers.
 Scabies – This infection is caused by microscopic mites that burrow into the skin to live
and feed. The infection spreads from skin-to-skin contact or from infested items such as
furniture and bed linens.

35
  Ringworm – You can get this fungal infection from skin-to-skin contact with an infected
person or animal.
 Shingles – Shingles develops from the same virus that causes chicken pox.

Symptoms

Contagious skin diseases present with a wide range of symptoms. Some have similarities such as
rashes, but most are very different.

 Impetigo – Red sores around the nose, mouth, hands and feet. Honey-colored crusts
develop after the sores rupture. Impetigo may cause mild itching and soreness.
 Molluscum contagiosum – Small, firm bumps that are pink or skin-colored with a dimpled
center. They turn red as the immune system fights the infection. Some bumps may itch but
are otherwise painless. Molluscum contagiosum often appears on the face, neck, hands,
arms and armpits.
 Fungal infections – Rash in moist areas of the body where skin rubs up against skin, such
as between the toes, under the breasts and in the genital area.
 Athlete’s foot – A cracked or blistered rash that causes stinging, itching and burning and
possibly an unpleasant odor. Usually starts between the toes but can also appear on the
soles and sides of the feet, and can spread to the toenails, groin and armpits.
 Scabies – Itching that keeps you up at night, rash with small bumps that look like hives,
sores from scratching that can become infected, and crusty areas in severe cases. Mites can
burrow anywhere on the body but prefer between the wrists, elbows, fingers, around
fingernails, the buttocks, belt line, penis and around the nipples.
 Ringworm – A fungal infection that starts as a red scaly area. The area spreads outward
and forms a circular ring with a slightly wavy border. The inside of the circle may look
clear, scaly or bumpy and red. Sometimes several rings appear and overlap.
 Shingles – Pain, burning, numbness or tingling, red rash, blisters that rupture and crust, and
itching. Most often appears as a single strip of blisters that wrap around your torso, but can
also develop around an eye, neck or face. Shingles may also cause fever, headache, fatigue
and light sensitivity.

3.1.4 Indirect Contact

Contact with contaminated objects or surfaces indirect contact transmission involves inanimate
objects called fomites that become contaminated by pathogens from an infected individual or
reservoir (Figure 2). For example, an individual with the common cold may sneeze, causing
droplets to land on a fomite such as a tablecloth or carpet, or the individual may wipe her nose and
then transfer mucus to a fomite such as a doorknob or towel. Transmission occurs indirectly when
a new susceptible host later touches the fomite and transfers the contaminated material to a
susceptible portal of entry. Fomites can also include objects used in clinical settings that are not
properly sterilized, such as syringes, needles, catheters, and surgical equipment. Pathogens
transmitted indirectly via such fomites are a major cause of healthcare-associated infections

36
Fig.1.6a: Contaminated Doorknobs. Fig.1.6b: Contaminated towels. Fig.1.6c: Contaminated
syringes
3.1.5 Blood Borne
Contact with blood or body fluids coughing and Sneezing: Teach children (and adults) to cough
or sneeze into tissues or their sleeve and not onto surfaces or other people. If children and adults
sneeze into their hands, hands should be washed immediately.

Hand washing Procedures: Washing your hands is one of the easiest and best ways to prevent the
spread of diseases. Hands should be washed frequently including after toileting, coming into
contact with bodily fluids (such as nose wiping), before eating and handling food, and any time
hands are soiled. It is also important that children’s hands be washed frequently. Water basins and
pre-moistened cleansing wipes are not approved substitutes for soap and running water. Alcohol-
based hand sanitizers containing at least 60% alcohol may be used when soap and water are not
available and hands are not visibly soiled. However, sanitizers do not eliminate all types of germs
so they should be used to supplement hand washing with soap and water. The general hand
washing procedure includes the following steps:

• Wet hands under warm running water.

• Apply liquid soap. Antibacterial soap is not recommended.
• Vigorously rub hands together for at least 20 seconds to lather all surfaces of the hands. Pay
special attention to cleaning under fingernails and thumbs.
• Thoroughly rinse hands under warm running water.
•Dry hands using a single-use disposable towel or an air dryer.
•Turn off the faucet with the disposable towel, your wrists, or the backs of your hands.
Blood borne Exposures Blood borne pathogens, such as Hepatitis B virus (HBV), Hepatitis C virus
(HCV) and human immunodeficiency virus (HIV), can be found in human blood and other body
fluids. Blood borne pathogens can be transmitted when there is direct contact with blood or other
potentially infected material. This can include blood entering open cuts or blood splashing into
mucous membranes (eyes, nose or mouth). All human blood should be treated as if it is infectious.

For more information, visit the Michigan Department of Education’s Blood borne Pathogens
and School Employees website at http://www.michigan.gov/mde/0,4615,7-140-
28753_64839_38684_29233_29803-241996--,00.htpps

37
3.2 Problems of Communicable Diseases among School Age

Problems caused by communicable diseases in schools include:

1. Absenteeism: school age children suffering from communicable disease may not have
chance of coming to school regularly. And even if they come, there is possibility of
infecting others, which could lead to more serious public health problems.
2. Stunted growth: communicable disease can cause stunted growth among school age
children as their normal body function is affected by the pathogens and that could affect
the learning process of the school age.
3. Attention deficit: communicable disease can result to attention deficit among the learners.
They may not be able to pay attention during the lesson as their body is fighting the
infection.
4. Body deformity: untreated cases of communicable diseases in the school can lead to
having permanent deformity in the body.
5. Death: serious cases of communicable diseases that rae not well treated in good time can
lead to the loss of life of the infected person.

Some of the common communicable diseases prevalent among school age include; malaria,
diaorrhea, dysentery, dental problems, tuberculosis, eye problems, skin diseases, sexual
transmitted diseases, sexual transmitted infection. All these diseases are result of poor personal
and environmental hygiene. If community and schools can enforce personal and environmental
hygiene, it will help in reducing the severity of the case which can be reduced to the barest
minimum.

4.0 Self-Assessment Exercise

1. Mention routs of communicable diseases transmission.

2. Describe the steps to be taken in hand washing.

3. Enumerate the problems associated with communicable diseases

Answers to Self-Assessment Exercise

1. the most common routes of transmission are:

• Fecal-oral: Contact with human stool; usually ingestion after contact with contaminated food or
objects
• Respiratory: Contact with respiratory particles or droplets from the nose, throat, and mouth
• Direct skin-to-skin contact: Contact with infected skin
38
• Indirect contact: Contact with contaminated objects or surfaces
• Blood borne: Contact with blood or body fluids Coughing and Sneezing Teach children (and
adults) to cough or sneeze into tissues or their sleeve and not onto surfaces or other people. If
children and adults sneeze into their hands, hands should be washed immediately.

2. Hand washing Procedures Washing your hands is one of the easiest and best ways to prevent
the spread of diseases. Hands should be washed frequently including after toileting, coming into
contact with bodily fluids (such as nose wiping), before eating and handling food, and any time
hands are soiled. It is also important that children’s hands be washed frequently. Water basins and
pre-moistened cleansing wipes are not approved substitutes for soap and running water. Alcohol-
based hand sanitizers containing at least 60% alcohol may be used when soap and water are not
available and hands are not visibly soiled. However, sanitizers do not eliminate all types of germs
so they should be used to supplement hand washing with soap and water. The general hand
washing procedure includes the following steps:

• Wet hands under warm running water.

• Apply liquid soap. Antibacterial soap is not recommended.
• Vigorously rub hands together for at least 20 seconds to lather all surfaces of the hands. Pay
special attention to cleaning under fingernails and thumbs.
• Thoroughly rinse hands under warm running water.
•Dry hands using a single-use disposable towel or an air dryer.
•Turn off the faucet with the disposable towel, your wrists, or the backs of your hands.
3. Problems caused by communicable diseases in schools include:
1. Absenteeism: school age suffering from communicable disease may not have chance of
coming to school regularly. And even if he comes there is possibility of infecting others,
which could lead to more serious public health problems.

2. Stunted growth: communicable disease can cause stunted growth among school age as their
normal body function is affected by the pathogens and that could affect the learning process
of the school age.

3. Attention deficit: communicable disease can result to attention deficit among the learners.
They may be unable to pay attention during the lesson as their body is fighting the infection.

4. Body deformity: untreated cases of communicable diseases in the school can lead to having
permanent deformity in the body.

5. Death: serious cases of communicable diseases that are not well treated in good time can
lead to the loss of life of the infected person.

39
5.0 Conclusion
The common communicable diseases prevalent among school age include; malaria, dysentery,
dental problems, tuberculosis, eye problems, skin diseases, sexual transmitted diseases, sexual
transmitted infection. All these diseases resulted due to poor personal and environmental hygiene.

6.0 Summary
Communicable diseases are the main problem of stunted growth, absenteeism, attention deficit,
body deformity and sometimes death among school age children.

7.0 Reference/Further Readings

Ageeb A. School Health Programme, policies and strategies of school health at national on state
level, some health. Problems of school children. Sudan National school health workshop.
1998:7–8. [Google Scholar]

Charles D. (und.). How Diseases Spread Through the Fecal-Oral Route

https://www.verywellhealth.com/what-is-the-fecal-oral-route-1760046 Retrieved 20th July, 2019.

Ford ES, Croft JB, Mannino DM, Wheaton AG, Zhang X, Giles WH. Chronic obstructive
pulmonary disease (COPD) surveillance–United States, 1999–2011: Chest. 2013
Jul;144(1):284-305. doi: 10.1378/chest.13-0809.

Michigan Department of Education’s Blood borne Pathogens

and School Employees website at http://www.michigan.gov/mde/0,4615,7-140-
28753_64839_38684_29233_29803-241996--,00.ht Retrieved 20th July, 2019.

National Institutes of Health, National Heart, Lung and Blood Institute (NHLBI). Guidelines for
the diagnosis and management of asthma (EPR-3) [Internet]. Bethesda, MD: NHLBI.
Available from: http://www.nhlbi.nih.gov/guidelines/asthma Retrieved on 19th September,
2019

World Health Organization. Fact sheet No. 391—Drinking Water. June 2005.
http://www.who.int/mediacentre/factsheets/fs391/en. Retrieved 20th July, 2019.

40
Module 2: Communicable Diseases

In this module different type of communicable diseases which include diseases that can be
transmitted through Indirect contact (Air bone, Water and food Bone, Vector Bone Diseases) and
Direct Contact (Sexually Transmitted Infection) will be discussed with their causative agents, signs
and symptoms as well as preventive measures.

Unit 1 Indirect Contact (water and Food born)

Unit 2 Vector Bone
Unit 3 Direct Contact
Unit 4 Tuberculosis and Rabies
Unit 5 Transmission Process and Preventive Measures of Communicable Diseases

Unit 1 Indirect Contact (Water and Food Bone Diseases)

CONTENTS
1.0 Introduction
2.0 intended learning outcomes (ILOs)
3.0 Main Content
3.1 Hepatitis B
3.1.1 Epidemiology
3.1.2 Control measures
3.2 Poliomyelitis (Polio)
3.2.1 Types of Polio
3.2.2 Causative Agent
3.2.3 Sign and Symptoms
3.2.4 Reservoir
3.2.5 Mode of Transmission
3.2.6 Incubation Period
3.2.7 Susceptibility and Resistance
3.2.8 Modes of Prevention and Control
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Readings

1.0 Introduction

Indirect contact infection occurs when there is no direct human-to-human contact. Contact occurs
from a reservoir through vector to contaminated surfaces or objects. Vectors could be mosquitos,
flies, ticks, and rodents. In this unit you will learn about Hepatitis B and Poliomyelitis.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:

 identify the transmission process of Hepatitis B
 describe the prevention and control measures of hepatitis.

41
 distinguish the different types of poliomyelitis.
 recognise the preventive measures of poliomyelitis

3.0 Main Content

3.1 Hepatitis B (HBV)

Occurrence: Worldwide
Organism: Hepatitis B virus (HBV)
Reservoir: Humans
Transmission: Blood and blood products
Control: Counselling
Hygiene
Blood Screening
Vaccination

Hepatitis B is not transmitted by the faeco-oral route but is a blood-borne agent, transmitted by
inoculation. Hepatitis B virus causes long-incubation hepatitis. It also gives rise to one of the 10
most common cancers, heptocellular carcinoma. There is evidence that HBV is the aetiological
agent in up to 80% of cases.

Fig 2.1 Hepatitis B

3.1.1 Epidemiology
The carrier state (defined as the presence of HbsAg for more than 6 months rises from 0.1% in
parts of Europe to 15% in several tropical countries. Globally, early childhood infections are the

42
most common and most important. In China, Taiwan and Hong Kong, a large number of infections
are acquired in the perinatal period, usually from a carrier mother. (Lucas and Gilles, 2003).
Transmission may occur by:
 Transfusion of blood or blood products;
 Accidental inoculation, e.g repeated use of hypodermic needles without adequate
sterilization, in particular: drug addicts, tattooing and ritual scarification;
 Insects bites
 Perinatally – from a carrier mother;
 Sexual intercourse – hetero and homosexual;
 Serious exudates of skin ulcers;
 Injury – associated sports or jobs

3.1.2 Control Measures

Control is carried out by a combination of:
(i) counselling
(ii) hygiene practice in high risk areas
(iii) vaccination of at-risk individuals
(iv) selective use of hepatitis B immunoglobin (HbIG).
A recombinant HbsAg vaccine is now widely used. Three doses (at 0,1 and 6 months) are
required for complete protection. Vaccination is required for groups at high risk of infection
(e.g health-care staff in contact with blood or patients, homosexuals, drug users etc, depending
on epidemiological patterns, socio-economic factors, cultural and sexual practices. In areas of
the world where perinatal infection is common, immunization of susceptible women of
childbearing age and of infants, particularly those born to carrier mothers, is desirable.
Administration of HbIG confers extra protection to these infants and those individuals
accidentally exposed (e.g, health workers following needle-stick injuries and sexual partners
of acute cases).

43
WHO has recommended that all children should be vaccinated during the first year of life. In
countries where perinatal transmission is frequent, vaccination should be done at or soon after
birth.
3.2 Poliomyelitis (Polio)

It is one of the dangerous infectious diseases that affect the child. The disease kills a lot of children

who are not immunized, and those who escaped death are left paralyzed either on both legs and

half of the body involving one leg and one arm. This situation makes both parent and the child

unhappy.

Polio is a serious viral disease that is common among children. The polio virus attacks the spinal

cord of the child. Since spinal cord is important in human movement, the attack causes motor

paralysis and muscles atrophy (failure to develop the body muscle normally) which often result in

permanent deformity.

Fig 2.2 poliomylitis

44
3.2.1 Types of Polio

There are two type of polio namely;

i. Non – paralytic: this type of polio does not result in paralysis and last only a few years.

ii. Paralytic polio: this involves a weakening and paralysis of the muscles, (infantile

paralysis). Site of the paralysis depends on the location of nerve cell in the central nervous

system destroyed by the virus.

3.2.2 Causative Agent

45
Polio is caused by a group of viruses called polio virus which attack the central nervous system

(spinal cord) and causes paralysis to the legs, arms, and body, and also waste of muscle of right

thigh and calf, also flat foot.

3.2.3 Signs and symptoms

Polio is characterized by fever, motor paralysis, muscle atrophy, severe headache and sore throat.

There may be stiffness of the neck and back with or without paralysis.

3.2.4 Reservoir

Man is the sole reservoir of polio virus.

3.2.5 Mode of Transmission

Polio is transmitted by direct contact with the carrier or infected person through touching, kissing

or by contact with contaminated materials such as faeces and secretions from the pharynx of an

infected person. In rare instances the virus may be transmitted through fresh milk.

3.2.6 Incubation Period

The incubation period for the disease on average is 7 – 12 days. But it can start from 3days to 4 or

more.

3.2.7 Susceptibility and Resistance

Polio can occur in all ages, but children are mostly susceptible. This means that children are more

likely to suffer from the disease than an adult when both are exposed to infection. Some amount

of immunity or resistance is usually provided after recovery from an attack. This is usually enough

to provide adequate resistance against the disease for life. The best way of resisting polio disease

is through formal immunization.

3.2.8 Modes of Prevention and Control

46
1. Immunization: this is the best way of preventing and controlling of polio disease, here two

types of vaccines are available;

i. Sabin vaccine (weakened or attenuated virus). Three drops of this vaccine is given orally to

infant. For children every 4weeks for 3 dozens. The first doze is given at 2months, second doze at

3month and 3rd doze at 4 months. A booster doze is given to the child when he/she is about to enter

school (may be at 6 years) and another one at the age of 15. The Sabin vaccine is the more

commonly used form of polio immunization in Nigeria.

Fig 2.3 polio immunization

ii. The second type of vaccine is the sulked (killed virus) which is given by injection to the child

at 2months with an interval of 4weeks. Altogether 3 doses as in the case of oral vaccine.

Polio vaccine is give along with vaccines against diphtheria and tetanus as triple toxoid or DPT

(diphtheria, pertussis and tetanus) in the EPI programme.

47
2. Sanitary disposal of faeces and pharyngeal secretions: since faeca contamination is a source

of infection, faeces should be properly disposed. Hands should be thoroughly washed after going

to the toilet.

Both parents and food handlers must wash their hands with soap after using the toilet or before

giving food to children. Polio is a disease associated with low standards of personal and public

hygiene, therefore, good personal health and food hygiene is inevitable in preventing this disease.

3. Good nutrition: the nutritional status of a child plays important roles in resisting diseases. This

means that a child who is well nourished may have resistance against polio especially against

paralytic type of polio that causes paralysis.

4.0 Self-Assessment Exercises

1. Enumerate the Hepatitis B transmission process
2. Describe the control measures of Hepatitis B
3. Outline the different types of poliomyelitis.

Answers to Self-Assessment Exercises

Q.1.Transmission may occur by:

 Transfusion of blood or blood products;
 Accidental inoculation, e.g repeated use of hypodermic needles without adequate
sterilization, in particular: drug addicts, tattooing and ritual scarification;
 Insects bites
 Parentally – from a carrier mother;
 Sexual intercourse – hetero and homosexual;
 Serious exudates of skin ulcers;
 Injury – associated sports or Jobs

Q2. Control Measures

Control is carried out by a combination of: (i) counselling; (ii) hygiene practice in high risk areas;
(iii) vaccination of at-risk individuals; and (iv) selective use of hepatitis B immunoglobin (HbIG).
A recombinant HbsAg vaccine is now widely used. Three doses (at monthly interval) are required
for complete protection. Vaccination is required for groups at high risk of infection (e.g health-

48
care staff in contact with blood or patients, homosexuals, drug users, etc depending on
epidemiological patterns, socio-economic factors, cultural and sexual practices. In areas of the
world where perinatal infection is common, immunization of susceptible women of childbearing
age and of infants, particularly those born to carrier mothers, is desirable. Administration of HbIG
confers extra protection to these infants and those individuals accidentally exposed (e.g health
workers following needle-stick injuries and sexual partners of acute cases).
WHO has recommended that all children should be vaccinated during the first year of life. In
countries where perinatal transmission is frequent, vaccination should be done at or soon after
birth.
Q3. There are two type of polio namely;

i. Non – paralytic: this type of polio does not result in paralysis and last only a few years.

ii. Paralytic polio: this involves a weakening and paralysis of the muscles, (infantile
paralysis). Site of the paralysis depends on the location of nerve cell in the central nervous
system destroyed by the virus.

5.0 Conclusion

Hepatitis is currently more killer disease than HIV/AIDS. It does not show early until at chronic
stage. Therefore regular screening is very important in the early detection of the disease. Hepatitis
B is not transmitted by the faeco-oral route but is a blood-borne agent, transmitted by inoculation.
Poliomylitis is a disease that mostly affects children of under-five. It is one of the major cause
child mortality. The disease can be prevented through improving personal hygiene and
immunisation services. The disease is having high prevalence in developing countries where low
socio economics and low level of education.
6.0 Summary
Hepatitis is a viral infection which kills millions of people worldwide. It is transmitted through
blood, blood products, and sexual intercourse. It can be prevented through counselling; hygiene
practice in high risk areas; vaccination of at-risk individuals, three doses (at monthly interval) are
required for complete protection.
Polio is a viral disease that is common among children. The polio virus attacks the spinal cord of

the child. Since spinal cord is important in human movement, the attack causes motor paralysis

49
and muscles atrophy (failure to develop the body muscle normally) which often result in permanent

deformity.

7.0 Reference/Further Readings

Lucas .A. O. & Gilles H. M. (2003)..Short Textbook of Public Health Medicine for the Tropics.
Revised fuorth Edition. India, Book Power Edition,.

Adeniyi J.D (1993). Effective Teaching of Health Education in Primary Schools: the challenge in
the 90s. Niger School Health Journal; 8 (1): 26–34.

Miller,SS (2010). The Complete Home Medical Encyclopedia – symptoms. London:Macmillan

London Ltd.

Ojugo AI. (2005). Status of Health Appraisal Services for Primary School Conurnal hildren in
Edo state Nigeria. Int.. Electron Journal of Health Educ.8:146–52.

Smolensky, J and Haar, F. (1972). Principles of Community Health (3rd ed), Philadelphia: WB
sauders ND Co.

50
Unit 2 Vector Bone Diseases (Malaria and Onchocerciasis)
CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Malaria
3.1.1 Causes of Malaria
3.1.2 Mode of Transmission
3.1.3 The Malaria Life Cycle
3.1.4 Vulnerability
3.1.5 Classification of Malaria
3.1.6 Prevention and Control
3.2 Onchocerciasis
3.2.1 Signs and Symptoms
3.2.2 Life Cycle
3.2.3 Prevention and Control Measures
4.0 Self-Assessment Exercise
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

Vectors are living organisms that can transmit infectious diseases between humans or from animals
to human. Many of these vectors are bloodsucking insects, which ingest disease-producing
microorganisms during a blood meal from an infected host and later inject into a new host during
their subsequent meal. Mosquitos, ticks, flies, bugs and some freshwater aquatic snails. In the
previous unit you have learnt about Hepatitis B and Poliomyelitis and in this unit you will learn
malaria and onchocerciasis.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:
 identify the causative agent of malaria
 describe the transmission process
 explain the prevention and control measures of malaria.
 outline the signs and symptoms of onchocerciasis.
 discuss the prevention and control measures of onchocerciasis.

3.0 Main Content

51
3.1 Malaria

World Health Organization (WHO, 2011) Reported that a child dies every 45 seconds as a result
of the disease. Malaria is a vector-borne disease caused by a single-celled protozoan parasite called
Plasmodium, transmitted by female mosquitoes. Malaria is a common and life-threatening disease
in many tropical and subtropical areas and it is currently endemic in 99 countries. In 2010, there
were an estimated 219 million malaria episodes (uncertainty range 154–289 million), of which
approximately 81% were in Africa, and an estimated 660,000 malaria deaths (uncertainty range
490 000 to 836 000), of which 91% were in Africa. Approximately 86% of malaria deaths globally
are among children under five years old and an estimated 10 000 pregnant women and 200 000
newborn babies die annually due to malaria during pregnancy. Estimated malaria incidence has
been reduced by 17% and malaria-specific mortality rates by 26% globally since 2000. These rates
of decline are lower than the 50% target reductions agreed internationally for 2010, but nonetheless
represent a major achievement (WHO, 2013).

3.1.1 Causes of Malaria

The four species of Plasmodium which are known to cause disease in man are:

Plasmodium vivax (Tertian): It is the most common species in the World. It is the largest of the
malaria parasites found in humans. The length of its asexual cycle is 48 hours. Relapses are
common in vivax malaria due to emergence of new blood forms from maturing secondary liver
schizonts. In tropical areas, relapses may arise within three to four months of primary attack, while
in subtropical areas relapses occur only after nine months or more. However, it has been estimated
that more people worldwide live at risk from Plasmodium vivax than Plasmodium falciparum and
as a result suffer increased morbidity from Plasmodium vivax.

Plasmodium ovale, (Tertian): It is a relatively a rare species with a frequency of less than 5%. It
may sometimes be confused with P. vivax. The length of its asexual cycle is 48 hours. Relapses
occur as in P. vivax but the disease tends to be more chronic.

Plasmodium malariae (Quartan): It is a less common species whose length of its asexual cycle is
72 hours. P. malariae is associated with quartan malaria.

Plasmodium falciparum (Sub-Tertian): It is the commonest species in Africa and it accounts for
95 - 98% of all malaria infections. It is responsible for severe illness, cerebral malaria and other
complications and may cause death. The length of asexual cycle is about 48 hours. Fever is
produced when the schizonts are mature i.e. at 48 hours interval. Sub-tertian means that diurnal
periodicity is common. The liver stage of development take about 14 days. In our environment,
you may have noticed that many malaria laboratory tests report the presence of P. falciparum. This
is because it is the most common cause of malaria in our environment. Indeed in Africa,
Plasmodium falciparum is the most common type of malaria parasite transmitted in Africa, south
of the Sahara, accounting in large part for the extremely high mortality in this region. Plasmodium
falciparum, the dominant species in Africa, is the deadliest and is responsible for approximately
90% of malaria deaths per year, (White, 2011).

52
Fig 2.4 mosquito (malaria)

White, (2011) explained that each species of the Plasmodium parasite differs in phenotype,
immune response, geographical distribution, and relapse pattern and drug response. Female
mosquitoes transmit malaria as they feed on blood; they need the high levels of proteins in the
blood meal for their eggs to develop. They are attracted to humans by smell and vision. Slender,
sharp, saw toothed styles on the end of the female mosquito’s proboscis pierce the skin and probe
for a suitable small blood vessel. While sucking up the blood, the mosquito pumps saliva into the
host. Chemicals in the saliva prevent the blood from clotting and act as an anaesthetic to stop the
host feeling the mosquito while it is feeding. The characteristic red, itchy swelling of a mosquito
bite is due to an allergic reaction to the left over saliva. Male mosquitoes do not transmit the disease
as they feed only on plant juices.

3.1.2 Mode of Transmission

The transmission of malaria depends on interaction of the following factors: Presence of the
infective vector, susceptible human host and suitable environment for complete saprogenic cycle.
Malaria is transmitted by the female Anopheles mosquito which requires blood for the
development of its eggs. These eggs are laid on stagnant water or slow flowing water where they
stay for 2-3 days before they hatch to release mosquito larvae. The larvae grow beneath the water
surface and become pupa. After a few days the pupa develops into adult mosquitoes and flies away.

53
The development of mosquitoes from egg to larvae to adults takes 7-14 days at a temperature of
31 or 20 days at 20oC. The sporozoites are the infective stages of malaria parasites in the mosquito.
This process called sporogonic cycle takes about 10-14days depending on environmental
temperature. When a mosquito carrying sporozoites bites a person, it passes the parasites into the
blood of that person, thereby infecting that person with malaria.

3.1.3 The Malaria Life Cycle

The Malaria parasite lifecycle begins when an infected adult female Anopheles mosquito bites a
human being to feed on his or her blood. As it feeds on this blood, it releases malaria sporozoites
(parasites) into the blood stream of the host (human being). This is the infective bite. Once the
parasites enter the human blood stream they move quickly to the liver cells where they develop
and multiply (schizogony). The infected liver cells damage and release numerous merozoites into
the blood, which invade red blood cells (RBCs). This stage takes 9-14 days. Within the RBCs the
parasites develop from “rings” into blood schizonts. The schizonts then rupture the RBCs releasing
numerous merozoites which invade new RBCs. When the infected red blood cells damage this
process initiates the chills and fever which are characteristic of Malaria. Indeed, the peaks of fever
experienced during malaria coincide with the release into blood circulation of malaria parasites
(merozoites) from damage RBCs. The period between the infective bite and the onset of symptoms
(i.e fever, chills etc,) is called the incubation period of malaria. As mentioned earlier, the
incubation period is usually 7-14 days but may be shorter as in Plasmodium falciparum or longer
in the case of Plasmodium vivax and Plasmodium malariae, (White, 2011).

Fig 2.5 the malaria life cycle

54
Only female mosquitoes feed on blood; male mosquitoes feed on plant nectar and do not transmit
the disease. Females of the mosquito genus Anopheles prefer to feed at night. They usually start
searching for a meal at dusk, and continue through the night until they succeed, (Arrow,
Panosian & Gelband, 2004). Malaria parasites can also be transmitted by blood transfusions,
although this is rare, (Owusu-Ofori, Parry & Bates, 2010). Check there are many repetition of
ideas in malaria section which you need to correct.

3.1.4 Vulnerability

Pregnant women and children under the age of five are most vulnerable to malaria infections
because they have a lower natural immunity to the disease compared to others in the community.
Adults can also be affected by malaria, however if they have lived in the same area for long perio
d of time they are likely to build up some immunity to the parasite. This does not meanthat they a
re not infected but have less severe symptoms. People who travel frommalaria free areas to malar
ia endemic areas are also at risk of contracting the disease. Holiday makers and immigrant worke

55
rs can be vulnerable to infections as they have no immunity to the disease. Drugs are available th
at can be given by appropriate health workers to people treat when they become infected.

3.1.5 Classification of Malaria

Malaria is classified into either "severe" or "uncomplicated" by the World Health Organisation
(WHO). It is deemed severe when any of the following criteria are present, otherwise it is
considered uncomplicated, (World Malaria Report, 2017)

 Decreased consciousness
 Significant weakness such that the person is unable to walk
 Inability to feed
 Two or more convulsions
 Low blood pressure (less than 70 mmHg in adults and 50 mmHg in children)
 Breathing problems
 Circulatory shock
 Kidney failure or hemoglobin in the urine
 Bleeding problems, or hemoglobin less than 50 g/L (5 g/dL)
 Pulmonary oedema
 Blood glucose less than 2.2 mmol/L (40 mg/dL)
 Acidosis or lactate levels of greater than 5 mmol/L
 A parasite level in the blood of greater than 100,000 per microlitre (µL) in low-intensity
transmission areas, or 250,000 per µL in high-intensity transmission areas

Cerebral malaria is defined as a severe P. falciparum-malaria presenting with neurological

symptoms, including coma (with a Glasgow coma scale less than 11, or a Blantyre coma scale
less than 3), or with a coma that lasts longer than 30 minutes after a seizure (World Malaria
Report, 2017)

3.1.6 Prevention and Control

Methods used to prevent malaria include medications, mosquito elimination and the prevention of
bites. The presence of malaria in an area requires a combination of high human population density,
high anopheles mosquito population density and high rates of transmission from humans to
mosquitoes and from mosquitoes to humans. If any of these is lowered sufficiently, the parasite
eventually disappears from that area, as happened in North America, Europe, and parts of the
Middle East. However, unless the parasite is eliminated from the whole world, it could re-establish
if conditions revert to a combination that favors the parasite's reproduce.

Prevention of malaria may be more cost-effective than treatment of the disease in the long run, but
the initial costs required are out of reach of many of the world's poorest people. There is a wide
difference in the costs of control (i.e. maintenance of low endemicity) and elimination programs
between countries. For example, in China—whose government in 2010 announced a strategy to
pursue malaria elimination in the Chinese provinces—the required investment is a small
proportion of public expenditure on health. In contrast, a similar program in Tanzania would cost

56
an estimated one-fifth of the public health budget, (Sabot, Cohen, Hsiang, Kahn, Basu, Tang,
Zheng, Gao, Zou, Tatarsky, Aboobakar, Usas, Barrett, Cohen, Jamison &Feachem, 2010).

In areas where malaria is common, children under five years old often have anemia, which is
sometimes due to malaria. Giving children with anemia in these areas preventive antimalarial
medication improves red blood cell levels slightly but does not affect the risk of death or need for
hospitalisation, (Athuman, Kabanywanyi &Rohwer, 2015).

Vector control refers to methods used to decrease malaria by reducing the levels of transmission
by mosquitoes. For individual protection, the most effective insect repellents are based on DEET
or picaridin, (Kajfasz, 2009). Insecticide-treated mosquito nets (ITNs) and indoor residual
spraying (IRS) have been shown highly effective in preventing malaria among children in areas
where malaria is common, (Tanser, Lengeler& Sharp, 2010). Prompt treatment of confirmed cases
with artemisinin-based combination therapies (ACTs) may also reduce transmission, (Palmer,
2012).

Mosquito nets help keep mosquitoes away from people and reduce infection rates and transmission
of malaria. Nets are not a perfect barrier and are often treated with an insecticide designed to kill
the mosquito before it has time to find a way past the net. Insecticide-treated nets are estimated to
be twice as effective as untreated nets, and offer greater than 70% protection compared with no
net, (Miller, Korenromp, Nahlen&Steketee, 2007).

Indoor residual spraying is the spraying of insecticides on the walls inside a home. After feeding,
many mosquitoes rest on a nearby surface while digesting the blood meal, so if the walls of houses
have been coated with insecticides, the resting mosquitoes can be killed before they can bite
another person and transfer the malaria parasite, (Enayati& Hemingway, 2010).

3.2 Onchocerciasis

Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic
worm Onchocerca volvulus. It is the second-most common cause of blindness due to infection,
after trachoma. It can cause severe skin and eye disease, including blindness. Worldwide, an
estimated 18 million people are infected and 270,000 blinded by the disease. Onchocerciasis is
endemic in Africa, where it is a leading cause of blindness, and in specific areas.

The parasite worm is spread by the bites of a black fly of the Simulium type. Usually, many bites
are required before infection occurs. These flies live near rivers, hence the common name of the
disease. Once inside a person, the worms create larvae that make their way out to the skin, where
they can infect the next black fly that bites the person. There are a number of ways to make the
diagnosis, including: placing a biopsy of the skin in normal saline and watching for the dsdlarva
to come out, looking in the eye for larvae, and looking within the bumps under the skin for adult
worms.

About 15.5 million people are infected with river blindness. Approximately 0.8 million have some
amount of loss of vision from the infection. Most infections occur in sub-Saharan Africa, although
cases have also been reported in Yemen and isolated areas of Central and South America. In 1915,

57
the physician Rodolfo Robles first linked the worm to eye disease. It is listed by the World Health
Organization (WHO) as a neglected tropical disease.

3.2.1 Signs and Symptoms

Symptoms include severe itching, bumps under the skin, and blindness. Adult worms remain in
subcutaneous nodules, limiting access to the host's immune system. Microfilariae, in contrast, are
able to induce intense inflammatory responses, especially upon their death. Wolbachia species
have been found to be endosymbionts of O. volvulus adults and microfilariae, and are thought to
be the driving force behind most of O. volvulus morbidity. Dying microfilariae have been recently
discovered to release Wolbachia surface protein that activates TLR2 and TLR4, triggering innate
immune responses and producing the inflammation and its associated morbidity. The severity of
illness is directly proportional to the number of infected microfilariae and the power of the resultant
inflammatory response.

Skin involvement typically consists of intense itching, swelling, and inflammation. A grading
system has been developed to categorize the degree of skin involvement:

 Acute papular onchodermatitis – scattered pruritic papules

 Chronic papular onchodermatitis – larger papules, resulting in hyperpigmentation
 Lichenified onchodermatitis – hyperpigmented papules and plaques, with edema,
lymphadenopathy, pruritus and common secondary bacterial infections
 Skin atrophy – loss of elasticity, the skin resembles tissue paper, 'lizard skin' appearance
 Depigmentation – 'leopard skin' appearance, usually on anterior lower leg
 Glaucoma effect – eyes malfunction, begin to see shadows or nothing

3.2.2 Life Cycle

The life of the parasite can be traced through the black fly and the human hosts in the following
steps:

1. A Simulium female black fly takes a blood meal on an infected human host, and ingests
microfilaria.
2. The microfilaria enter the gut and thoracic flight muscles of the black fly, progressing
into the first larval stage (J1.).
3. The larvae mature into the second larval stage (J2.), and move to the proboscis and into
the saliva in its third larval stage (J3.). Maturation takes about seven days.
4. The black fly takes another blood meal, passing the larvae into the next human host’s
blood.
5. The larvae migrate to the subcutaneous tissue and undergo two more molts. They form
nodules as they mature into adult worms over six to 12 months.
6. After maturing, adult male worms mate with female worms in the subcutaneous tissue to
produce between 700 and 1,500 microfilaria per day.
7. The microfilaria migrate to the skin during the day, and the black flies only feed in the
day, so the parasite is in a prime position for the female fly to ingest it. Black flies take
blood meals to ingest these microfilaria to restart the cycle.

58
3.2.3 Prevention and Control Measures

Prevention is by avoiding being bitten by flies. This may include the use of insect repellent and
proper clothing. Other efforts include those to decrease the fly population by spraying insecticides.
Efforts to eradicate the disease by treating entire groups of people twice a year are ongoing in a
number of areas of the world .Various control programs aim to stop onchocerciasis from being a
public health problem. The first was the Onchocerciasis Control Programme (OCP), which was
launched in 1974, and at its peak, covered 30 million people in 11 countries. Through the use of
larvicide spraying of fast-flowing rivers to control black fly populations, and from 1988 onwards,
the use of ivermectin to treat infected people, the OCP eliminated onchocerciasis as a public health
problem. The OCP, a joint effort of the World Health Organization, the World Bank, the United
Nations Development Programme, and the UN Food and Agriculture Organization, was
considered to be a success, and came to an end in 2002. Continued monitoring ensures
onchocerciasis cannot reinvade the area of the OCP.

In 1995, the African Programme for Onchocerciasis Control (APOC) began covering another 19
countries, mainly relying upon the use of the drug ivermectin. Its goal was to set up community-
directed treatment with ivermectin for those at risk of infection. In these ways, transmission has
declined. APOC closed in 2015 and aspects of its work taken over by the WHO Expanded Special
Programme for the Elimination of Neglected Tropical Diseases (ESPEN). As in the Americas, the
objective of ESPEN working with Government Health Ministries and partner NGDOs, is the
elimination of transmission of onchocerciasis. This requires consistent annual treatment of 80% of
the population in endemic areas for at least 10-12 years - the life span of the adult worm. No
African country has so far verified elimination of onchocerciasis, but treatment has stopped in
some areas (e.g. Nigeria), following epidemiological and entomological assessments that indicated
that no ongoing transmission could be detected. In 2015, WHO facilitated the launch of an
elimination program in Yemen which was subsequently put on hold due to conflict.

4.0 Self-Assessment Exercise

1. What are the causes of malaria?
2. Explain the transmission process of malaria
3. Describe the prevention and control measures of malaria.
4. Examine the signs and symptoms of onchocerciasis.

Answer to Self-Assessment Exercise

Q1. Causes of malaria

The four species of Plasmodium which are known to cause disease in man are:

Plasmodium vivax (Tertian): It is the most common species in the World. It is the largest of the
malaria parasites found in humans. The length of its asexual cycle is 48 hours. Relapses are

59
common in vivax malaria due to emergence of new blood forms from maturing secondary liver
schizonts. In tropical areas, relapses may arise within three to four months of primary attack, while
in subtropical areas relapses occur only after nine months or more. However, it has been estimated
that more people worldwide live at risk from Plasmodium vivax than Plasmodium falciparum and
as a result suffer increased morbidity from Plasmodium vivax.

Plasmodium ovale, (Tertian): It is a relatively a rare species with a frequency of less than 5%. It
may sometimes be confused with P. vivax. The length of its asexual cycle is 48 hours. Relapses
occur as in P. vivax but the disease tends to be more chronic.

Plasmodium malariae (Quartan): It is a less common species whose length of its asexual cycle
is 72 hours. P. malariae is associated with quartan malaria.

Plasmodium falciparum (Sub-Tertian): It is the commonest species in Africa and it accounts

for 95 - 98% of all malaria infections. It is responsible for severe illness, cerebral malaria and other
complications and may cause death. The length of asexual cycle is about 48 hours. Fever is
produced when the schizonts are mature i.e. at 48 hours interval. Sub-tertian means that diurnal
periodicity is common. The liver stage of development take about 14 days. In our environment,
you may have noticed that many malaria laboratory tests report the presence of P. falciparum. This
is because it is the most common cause of malaria in our environment. Indeed in Africa,
Plasmodium falciparum is the most common type of malaria parasite transmitted in Africa, south
of the Sahara, accounting in large part for the extremely high mortality in this region. Plasmodium
falciparum, the dominant species in Africa, is the deadliest and is responsible for approximately
90% of malaria deaths per year.

Species of the Plasmodium parasite differs in phenotype, immune response, geographical

distribution, and relapse pattern and drug response. Female mosquitoes transmit malaria as they
feed on blood; they need the high levels of proteins in the blood meal to develop their eggs. They
are attracted to humans by smell and vision. Slender, sharp, saw toothed styles on the end of the
female mosquito’s proboscis pierce the skin and probe for a suitable small blood vessel. While
sucking up the blood, the mosquito pumps saliva into the host. Chemicals in the saliva prevent the
blood from clotting and act as an aesthetic to stop the host feeling the mosquito while it is feeding.
The characteristic red, itchy swelling of a mosquito bite is due to an allergic reaction to the left
over saliva. Male mosquitoes do not transmit the disease as they feed only on plant juices.

Q2. Mode of transmission

The transmission of Malaria depends on interaction of the following factors: Presence of the
infective vector, susceptible human host and suitable environment for complete sporogonic cycle.
Malaria is transmitted by the female Anopheles mosquito which requires blood for the
development of its eggs. These eggs are laid on stagnant water or slow flowing water where they
stay for 2-3 days before they hatch to release mosquito larvae. The larvae grow beneath the water

60
surface and become pupa. After a few days the pupa develops into adult mosquitoes and flies away.
The development of mosquitoes from egg to larvae to adults takes 7-14 days at a temperature of
31 or 20 days at 20oC. The sporozoites are the infective stages of malaria parasites in the mosquito.
This process called sporogonic cycle takes about 10-14days depending on environmental
temperature. When a mosquito carrying sporozoites bites a person, it passes the parasites into the
blood of that person, thereby infecting that person with malaria.

Q3. Prevention and control

Methods used to prevent malaria include medications, mosquito elimination and the prevention of
bites. The presence of malaria in an area requires a combination of high human population density,
high anopheles mosquito population density and high rates of transmission from humans to
mosquitoes and from mosquitoes to humans. If any of these is lowered sufficiently, the parasite
eventually disappears from that area, as happened in North America, Europe, and parts of the
Middle East. However, unless the parasite is eliminated from the whole world, it could re-establish
if conditions revert to a combination that favors the parasite's reproduction.

Prevention of malaria may be more cost-effective than treatment of the disease in the long run, but
the initial costs required are out of reach of many of the world's poorest people. There is a wide
difference in the costs of control (i.e. maintenance of low endemicity) and elimination programs
between countries. For example, in China—whose government in 2010 announced a strategy to
pursue malaria elimination in the Chinese provinces—the required investment is a small
proportion of public expenditure on health. In contrast, a similar program in Tanzania would cost
an estimated one-fifth of the public health budget.

In areas where malaria is common, children under five years old often have anemia, which is
sometimes due to malaria. Giving children with anemia in these areas preventive antimalarial
medication improves red blood cell levels slightly but does not affect the risk of death or need for
hospitalization.

Vector control refers to methods used to decrease malaria by reducing the levels of transmission
by mosquitoes. For individual protection, the most effective insect repellents are based on DEET
or picaridin, (Kajfasz, 2009). Insecticide-treated mosquito nets (ITNs) and indoor residual spraying
(IRS) have been shown highly effective in preventing malaria among children in areas where
malaria is common. Prompt treatment of confirmed cases with artemisinin-based combination
therapies (ACTs) may also reduce transmission.

Mosquito nets help keep mosquitoes away from people and reduce infection rates and transmission
of malaria. Nets are not a perfect barrier and are often treated with an insecticide designed to kill
the mosquito before it has time to find a way past the net. Insecticide-treated nets are estimated to
be twice as effective as untreated nets, and offer greater than 70% protection compared with no
net.

Indoor residual spraying is the spraying of insecticides on the walls inside a home. After feeding,
many mosquitoes rest on a nearby surface while digesting the blood meal, so if the walls of houses

61
have been coated with insecticides, the resting mosquitoes can be killed before they can bite
another person and transfer the malaria parasite.

Q4. Signs and symptoms

Symptoms include severe itching, bumps under the skin, and blindness. Adult worms remain in
subcutaneous nodules, limiting access to the host's immune system. Microfilariae, in contrast, are
able to induce intense inflammatory responses, especially upon their death. Wolbachia species
have been found to be endosymbionts of O. volvulus adults and microfilariae, and are thought to
be the driving force behind most of O. volvulus morbidity. Dying microfilariae have been recently
discovered to release Wolbachia surface protein that activates TLR2 and TLR4, triggering innate
immune responses and producing the inflammation and its associated morbidity. The severity of
illness is directly proportional to the number of infected microfilariae and the power of the resultant
inflammatory response.

Skin involvement typically consists of intense itching, swelling, and inflammation. A grading
system has been developed to categorize the degree of skin involvement:

 Acute papular onchodermatitis – scattered pruritic papules

 Chronic papular onchodermatitis – larger papules, resulting in hyperpigmentation
 Lichenified onchodermatitis – hyperpigmented papules and plaques, with edema,
lymphadenopathy, pruritus and common secondary bacterial infections
 Skin atrophy – loss of elasticity, the skin resembles tissue paper, 'lizard skin' appearance
 Depigmentation – 'leopard skin' appearance, usually on anterior lower leg
 Glaucoma effect – eyes malfunction, begin to see shadows or nothing

5.0 Conclusion

Malaria is a febrile vector-borne disease in which a child dies every 45 seconds. Over 3 million
people are at risk of getting infected. It affects up to 250 million and kills nearly 800,000 people
per year.

Many people around the world more particularly those living in riverine areas are affected with
onchoceciasis. This infection is one of the major cause of blindness. Onchocerciasis is largely
preventable.

6.0 Summary

Malaria is a disease caused by a single-celled protozoan parasite called Plasmodium, transmitted

by female anopheles mosquitoes. Pregnant women and children under the age of five are most
vulnerable to malaria infections. Malaria is classified into either severe or uncomplicated. Malaria
can be prevented through medications, mosquito elimination, environmental sanitation, health
education and the prevention of bites.

The onchocerciasis parasite worm is spread by the bites of a black fly of the Simulium type.
Usually, many bites are required before infection occurs. These flies live near rivers, hence the

62
common name of the disease. Once inside a person, the worms create larvae that make their way
out to the skin, where they can infect the next black fly that bites the person.

7.0 References/Further Reading

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antimalarial treatment for children with anaemia".The Cochrane Database of Systematic
Reviews. CD010767. doi:10.1002/14651858.CD010767.pub2.
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Arrow KJ, Panosian C, Gelband H (2004). Saving Lives, Buying Time: Economics of Malaria
Drugs in an Age of Resistance. National Academies Press. p. 141.ISBN 978-0-309-09218-
0.Archived from the original on 2016-05-15.

Bardají A, Bassat Q, Alonso PL, Menéndez C (2012). "Intermittent preventive treatment of malaria
in pregnant women and infants: making best use of the available evidence". Expert Opinion
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PMID 22775553.

Caraballo H (2014). "Emergency department management of mosquito-borne illness: Malaria,

dengue, and west nile virus". Emergency Medicine Practice.16 (5).Archived from the
original on 2016-08-01.

Enayati A, Hemingway J (2010). "Malaria management: Past, present, and future". Annual Review
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Enayati AA, Hemingway J, Garner P (2007). Enayati A (ed.). "Electronic mosquito repellents for
preventing mosquito bites and malaria infection"(PDF). Cochrane Database of Systematic
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PMID 17443590.Archived from the original on 2016-05-03.

http://wikieducator.org/index.php?title=Lesson_1:Introduction_To_Malaria&printable=yes

Indoor Residual Spraying: Use of Indoor Residual Spraying for Scaling Up Global Malaria Control
and Elimination. WHO Position Statement(PDF) (Report). World Health Organization.
2006. Archived(PDF) from the original on 2008-10-02.

Instructions for treatment and use of insecticide-treated mosquito nets(pdf).World Health

Organization. 2002. p. 34. Archived(PDF) from the original on 2015-07-06.

Kajfasz P (2009). "Malaria prevention".International Maritime Health.60 (1–2): 67–70.

PMID 20205131.Archived from the original on 2017-08-30.

Lalloo DG, Olukoya P, Olliaro P (2006). "Malaria in adolescence: Burden of disease,

consequences, and opportunities for intervention". Lancet Infectious Diseases.6 (12): 780–
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63
Miller JM, Korenromp EL, Nahlen BL, W Steketee R (2007). "Estimating the number of
insecticide-treated nets required by African households to reach continent-wide malaria
coverage targets".Journal of the American Medical Association.297 (20): 2241–50.
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Mehlhorn H, ed. (2008). "Disease Control, Methods". Encyclopedia of Parasitology (3rd ed.).
Springer. pp. 362–66. ISBN 978-3-540-48997-9.

Meremikwu MM, Donegan S, Sinclair D, Esu E, Oringanje C (2012). Meremikwu MM (ed.).

Intermittent preventive treatment for malaria in children living in areas with seasonal
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Noor AM, Mutheu JJ, Tatem AJ, Hay SI, Snow RW (2009). "Insecticide-treated net coverage in
Africa: Mapping progress in 2000–07". Lancet.373 (9657): 58–67. doi:10.1016/S0140-
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Owusu-Ofori AK, Parry C, Bates I (2010). "Transfusion-transmitted malaria in countries where

malaria is endemic: A review of the literature from sub-Saharan Africa". Clinical Infectious
Diseases.51 (10): 1192–8. doi:10.1086/656806. PMID 20929356.

Palmer, J. "WHO gives indoor use of DDT a clean bill of health for controlling malaria".
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Sabot O, Cohen JM, Hsiang MS, Kahn JG, Basu S, Tang L, Zheng B, Gao Q, Zou L, Tatarsky A,
Aboobakar S, Usas J, Barrett S, Cohen JL, Jamison DT, Feachem RG (2010). "Costs and
financial feasibility of malaria elimination".Lancet.376 (9752): 1604–15.
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Tanser FC, Lengeler C, Sharp BL (2010). Lengeler C (ed.). "Indoor residual spraying for
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1075–81. doi:10.1016/j.ijpara.2004.04.010. PMID 15313134.

Harder A (2002). "Chemotherapeutic approaches to nematodes: current knowledge and outlook".

Parasitology Research. 88 (3): 272–7. doi:10.1007/s00436-001-0535-x. PMID 11954915.

Wolstenholme AJ, Rogers AT (2005). "Glutamate-gated chloride channels and the mode of
action of the avermectin/milbemycin anthelmintics". Parasitology. 131 (Suppl:S85–95):
S85–95. doi:10.1017/S0031182005008218. PMID 16569295.

Ejere HO, Schwartz E, Wormald R, Evans JR (2012). "Ivermectin for onchocercal eye disease
(river blindness)". Cochrane Database Syst Rev. 8 (8): CD002219.
doi:10.1002/14651858.CD002219.pub2. PMC 4425412. PMID 22895928

Unit 3: Tuberculosis and Rabies

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Tuberculosis
3.1.1 Primary Complex

66
 3.1.2 Early Complications
3.1.3 Bacteriology
3.1.4 Epidemiology
3.1.5 Reservoir
3.1.6 Transmission
3.1.7 Host Factor
3.1.8 Control
3.2 General Health Promotion
3.2.1 Specific Protection
3.2.2 BCG Vaccination
3.3 Rabies
3.3.1 What is Rabies?
3.3.2 Transmission
3.3.3 Symptoms
3.3.4 Acute Neurologic Period
3.3.5 Coma and Death
3.3.6 Incubation Period
3.3.7 Prodrome
3.3.8 Prevention of Rabies
3.3.9 Eliminating Rabies in Dogs
3.3.10 Awareness on Rabies and Preventing Dog Bites
3.3.11 Preventive Immunization in People
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0. Introduction

In the previous unit have learnt about malaria and onchocerciasis. In this unit you will learn about
tuberculosis and rabies. Both of these diseases become a serious public health problem which is
claiming many lives. But one good thing about these diseases, there are preventive measures such
as; improving personal hygiene, good nutrition proper housing and immunization and illuminate
the rabies from dogs.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:

 describe the primary complex and early complication of tuberculosis
 identify the transmission process of tuberculosis
 discuss the different types of rabies
 outline the prevention and control measures of rabies.

3.0 Main Content

3.1 Tuberculosis

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Occurrence: Worldwide
Organism: Mycobacterium tuberculosis (human and bovine strains).
Reservoir: Humans, Cattle
Transmission: Air borne droplets, droplets nuclei and dust
Milk and infected meat
Control: General improvement in housing, nutrition and personal hygiene
immunization with BCG
Chemoprophylaxis
Case finding and treatment, DOTs.
Tuberculosis remains one of the major health problems in many tropical countries; in some
countries the situation is being aggravated by dense overcrowding in urban slums. An estimated
8-10million people develop overt tuberculosis annually as a result of primary infection,
endogenous reactivation or exogenous re-infection. The coexistence of HIV infection and
tuberculosis has been hailed as one of the most serious threats to human health. Drug resistant
tuberculosis is on the increase in many countries of the world. Tuberculosis present a wide variety
of clinical forms, but pulmonary involvement is common and is most important epidemiologically
as it is primarily responsible for the transmission of the infection (Lucas and Gilles, 2003).
Figure 3.1 Tuberculosis

3.1.1 Primary Complex

On first infection, the patient develops the primary complex which consists of a small parenchymal
lesion and involvement of the regional lymph node; in the lungs, this constitutes the classical Ghon

68
focus, with a small lung lesion and invasion of the mediastinal lymph node. In most case the
primary complex heals spontaneously, with fibrosis and calcification of the lesions, but the
organisms may persist for many years within this focus.
3.1.2 Early Complications
In a small proportion of cases the primary complex progresses to produce more severe
manifestations locally (e.g. caseous pneumonia) or there may be haemotogenous dissemination to
other parts of the body. Thus within a few years of the primary infection, especially duringthe first
6 months, there is the danger of haemotogenous spread either focal (e.g. bone and joint lesions) or
disseminated (in the form of miliary tuberculosis and tuberculosis meningitis).
Secondary Infection
Apart from the primary complex and its early complication, the ‘adult’ pulmonary form of
tuberculosis may occur either as a result of the reactivation of an existing lesion or by exogenous
re-infection. Destruction of the lung parenchyma, with fibrosis and cavitation are important
features of this adult form. Clinically, it may present with cough, haemoptysis and chest pain, with
general constitutional symptoms-fever, loss of weight and malaise; often it remains virtually
asymptomatic especially in the early stage.
3.1.3 Bacteriology
The causative agent is mycobacterium tuberculosis the tubercle bacillus. The human type produces
most of the pulmonary lesions, also some extra pulmonary lesions; the bovine strain of the
organism mainly accounts for extra pulmonary lesions. Other types of M. Tuberculosis (avian and
a typical strains) rarely cause disease in humans, but infection may produce immunological
changes, with a non-specific tuberculin skin reaction. Tubercle bacilli survive for long period in
dried sputum and dust (Lucas and Gilles, 2003).
3.1.4 Epidemiology
Tuberculosis has a worldwide distribution. Until recently, it was absent from a few isolated
communities where the local populations are now showing widespread infections with severe
manifestations on first contact with tuberculosis.
3.1.5 Reservoir
Human are the reservoir of the human strain and patients with pulmonary infection constitute the
main source of infection. The reservoir of the bovine strain is cattle, with infected milk and meat
being the main source of infection.

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3.1.6 Transmission
Transmission of infection is mainly air-borne by droplets, droplets nuclei and dust; thus it is
enhanced by overcrowding in poorly ventilated accommodation. Infection may also occur by
ingestion especially of contaminated milk and infected meat.
3.1.7 Host Factors
The host response is an important factor in the epidemiology of tuberculosis. A primary infection
may heal, the host acquiring immunity in the process. In some cases the primary lesion progresses
to produce extensive disease locally, or infection may disseminate to produce metastic or military
lesions. Lesions that are apparently healed may subsequently break down with reactivation of
disease. Certain factors such as malnutrition, measles infection and HIV infection, use of
corticosteriods and other debilitating conditions predispose to progression and reactivation of the
disease.
3.1.8 Control
In planning a programme for the control of tuberculosis, the entire population can be conveniently
considered as falling into four groups:
 No previous exposure to tubercle bacilli – they would require protection from infection.
 Healed primary infection – they have some immunity but must be protected from
reactivation of disease and re-infection.
 Diagnosed active disease – they must have effective treatment and remain under
supervision until they have recovered fully.
 Undiagnosed active disease – without treatment the disease may progress with further
irreversible damage. As potential sources of infection, they constitute a danger to the
community.

The control of tuberculosis can be considered at the following levels of prevention:

 General health promotion
 Specific protection – active immunisation, chemoprophylaxis, control of animal
reservoir;
 Early diagnosis and treatment;
 Limitation of disability;
 Rehabilitation;

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  Surveillance

3.2 General Health Promotion

Improvement in housing (good ventilation, avoidance of overcrowding) will reduce the chances
of air-borne infections. Health education should be directed at producing better personal habits
with regard to spitting and coughing. Good nutrition enhances host immunity.

3.2.1 Specific Protection

Three measures are available: (i) active immunization with BCG (Bacille Calmette Guerin); (ii)
chemoprophylaxis; and (iii) control of animal tuberculosis.
3.2.2 BCG Vaccination
This vaccine contains live attenuated tubercle bacilli of the bovine strain. It may be administered
intradermal by syringe and needle or by the multiple-puncture technique. It confers significant but
not absolute immunity; in particular, it protects against the disseminated military lesions of
tuberculosis and tuberculosis meningitis.
3.3 Rabies

3.3.1 What is Rabies?

Rabies is a viral infection that mainly spreads through a bite from an infected animal. It is an RNA
virus of the rhabdovirus family. Rabies is an infectious viral disease that is almost always fatal
following the onset of clinical symptoms. In up to 99% of cases, domestic dogs are responsible for
rabies virus transmission to humans. Yet, rabies can affect both domestic and wild animals. It is
spread to people through bites or scratches, usually via saliva.

Rabies is a virus that is usually spread by the bite or scratch of an animal. By the time the symptoms
appear, it is generally too late to save the patient. However, a person who may have been exposed
to rabies can usually be treated effectively if they seek help at once.

However, globally, it remains a problem, and tens of thousands of deaths result from rabies each
year, mostly in rural areas of Southeast Asia and Africa. Over 95 percent of infections are caused
by dogs.

Fast facts on rabies

 Rabies is a viral disease that is nearly always transmitted by an infected animal bite.
 Anyone who receives a bite in a geographical area where rabies occurs should seek
treatment at once.

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  For treatment to be successful, it must be given before symptoms appear.
 Symptoms include neurological problems and a fear of light and water.
 Following the vaccination requirements for pets helps prevent and control rabies.

Without early treatment, it is usually fatal.

The virus can affect the body in one of two ways:

 It enters the peripheral nervous system (PNS) directly and migrates to the brain.
 It replicates within muscle tissue, where it is safe from the host's immune system. From
here, it enters the nervous system through the neuromuscular junctions.

Once inside the nervous system, the virus produces acute inflammation of the brain. Coma and
death soon follow.

There are two forms of the disease:

 Furious, or encephalitic rabies: This occurs in 80 percent of human cases. People with
furious rabies exhibit signs of hyperactivity, excitable behaviour, hydrophobia (fear of
water) and sometimes aerophobia (fear of drafts or of fresh air). Death occurs after a few
days due to cardio-respiratory arrest.

 Paralytic or "dumb" rabies: accounts for about 20% of the total number of human cases.
This form of rabies runs a less dramatic and usually longer course than the furious form.
Muscles gradually become paralyzed, starting at the site of the bite or scratch. A coma
slowly develops, and eventually death occurs. The paralytic form of rabies is often
misdiagnosed, contributing to the under-reporting of the disease.

Fig. 2.8: Vaccinate dogs and cats to protect them from rabies.

3.3.2 Transmission
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People are usually infected following a deep bite or scratch from an animal with rabies, and
transmission to humans by rabid dog’s accounts for 99% of cases.

It is passed on through saliva. Rabies can develop if a person receives a bite from an infected
animal, or if saliva from an infected animal gets into an open wound or through a mucous
membrane, such as the eyes or mouth. It cannot pass through unbroken skin.

Contraction of rabies through inhalation of virus-containing aerosols or through transplantation of

infected organs is rare. Contracting rabies through consumption of raw meat or animal-derived
tissue has never been confirmed in humans.

Raccoons, coyotes, bats, skunks, and foxes are the animals most likely to spread the virus.

Any mammal can harbor and transmit the virus, but smaller mammals, such as rodents, rarely
become infected or transmit rabies. Rabbits are unlikely to spread rabies.

3.3.3 Symptoms

The incubation period for rabies is typically 2–3 months but may vary from 1 week to 1 year,
dependent upon factors such as the location of virus entry and viral load. Initial symptoms of rabies
include a fever with pain and unusual or unexplained tingling, pricking, or burning sensation
(paraesthesia) at the wound site. As the virus spreads to the central nervous system, progressive
and fatal inflammation of the brain and spinal cord develops.

Early, flu-like symptoms, include:

 a fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or above

 headache
 anxiety
 feeling generally unwell
 sore throat and a cough
 nausea and vomiting
 discomfort may occur at the site of the bite

These can last from 2 to 10 days, and they worsen over time.

3.3.4 Acute Neurologic Period

Neurologic symptoms develop, including:

 confusion and aggression

 partial paralysis, involuntary muscle twitching, and rigid neck muscles
 convulsions
 hyperventilation and difficulty breathing
 hypersalivation or producing a lot of saliva, and possibly frothing at the mouth
 fear of water, or hydrophobia, due to difficulty swallowing

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  hallucinations, nightmares, and insomnia
 priapism, or permanent erection, in males
 photophobia, or a fear of light

Toward the end of this phase, breathing becomes rapid and inconsistent.

3.3.5 Coma and Death

If the person enters a coma, death will occur within a matter of hours, unless they are attached to
a ventilator.

Rarely, a person may recover at this late stage.

Why does rabies cause a fear of water?

Rabies used to be known as hydrophobia because it appears to cause a fear of water.

Intense spasms in the throat are triggered when trying to swallow. Even the thought of swallowing
water can cause spasms. This is where the fear comes from.

The excess saliva that occurs is probably due to the impact of the virus on the nervous system.

If the individual could swallow saliva easily, this would reduce the risk of spreading the virus to a
new host.

Rabies progresses in five distinct stages:

 incubation
 prodrome
 acute neurologic period
 coma
 death

3.3.6 Incubation Period

This is the time before symptoms appear. It usually lasts from 3 to 12 weeks, but it can take as
little as 5 days or more than 2 years.

The closer the bite is to the brain, the sooner the effects are likely to appear.

By the time symptoms appear, rabies is usually fatal. Anyone who may have been exposed to the
virus should seek medical help at once, without waiting for symptoms.

74
3.3.7 Prodrome

Fig. 2.9: During the prodrome stage of rabies, a person may experience coughing and fever.

3.3.8 Prevention of Rabies

Rabies is a serious disease, but individuals and governments can and do take action to control and
prevent, and, in some cases, wipe it out completely.

Fig. 2.10: Vaccination of Humans to Prevent the Spread of Rabies

In some areas the vaccination of humans is necessary to prevent the spread of rabies.
Strategies include:
 regular anti-rabies vaccinations for all pets and domestic animals
 bans or restrictions on the import of animals from some countries
 widespread vaccinations of humans in some areas
 educational information and awareness

Individual precautions
Individuals should follow some safety rules to reduce the chance of contracting rabies.

75
  Vaccinate pets: Find out how often you need to vaccinate your cat, dog, ferret, and other
domestic or farm animals, and keep up the vaccinations.
 Protect small pets: Some pets cannot be vaccinated, so they should be kept in a cage or
inside the house to prevent contact with wild predators.
 Keep pets confined: Pets should be safely confined when at home, and supervised when
outside.
 Report strays to the local authorities: Contact local animal control officials or police
departments if you see animals roaming
 Do not approach wild animals: Animals with rabies are likely to be less cautious than usual,
and they may be more likely to approach people.
 Keep bats out of the home: Seal your home to prevent bats from nesting. Call an expert to
remove any bats that are already present.

3.3.9 Eliminating Rabies in Dogs

Rabies is a vaccine-preventable disease. Vaccinating dogs is the most cost-effective strategy for
preventing rabies in people. Dog vaccination reduces deaths attributable to rabies and the need for
PEP as a part of dog bite patient care.

3.3.10 Awareness on Rabies and Preventing Dog Bites

Education on dog behaviour and bite prevention for both children and adults is an essential
extension of a rabies vaccination programme and can decrease both the incidence of human rabies
and the financial burden of treating dog bites. Increasing awareness of rabies prevention and
control in communities includes education and information on responsible pet ownership, how to
prevent dog bites, and immediate care measures after a bite. Engagement and ownership of the
programme at the community level increases reach and uptake of key messages.

3.3.11 Preventive Immunization in People

Human rabies vaccines exist for pre-exposure immunization. These are recommended for people
in certain high-risk occupations such as laboratory workers handling live rabies and rabies-related
(lyssavirus) viruses; and people (such as animal disease control staff and wildlife rangers) whose
professional or personal activities might bring them into direct contact with bats, carnivores, or
other mammals that may be infected.

Pre-exposure immunization is also recommended for travellers to rabies-affected, remote areas

who plan to spend a lot of time outdoors involved in activities such as caving or mountain-
climbing. Expatriates and long term travellers to areas with a high rabies exposure risk should be
immunized if local access to rabies biologics is limited. Finally, immunization should also be
considered for children living in, or visiting, remote, highrisk areas. As they play with animals,
they may receive more severe bites, or may not report bites.

4.0 Self-Assessment Exercise

1. Explain the primary complex and early complication of tuberculosis.
2. Describe the transmission process of tuberculosis
3. Critically examine any two type of rabies
4. Outline the strategies of an individual can take to rabies.

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Answers to Self-Assessment Exercise
Q1. Primary Complex
On first infection, the patient develops the primary complex which consists of a small parenchymal
lesion and involvement of the regional lymph node in the lungs, this constitutes the classical Ghon
focus, with a small lung lesion and invasion of the mediastinal lymph node. In most case the
primary complex heals spontaneously, with fibrosis and calcification of the lesions, but the
organisms may persist for many years within this focus.
Early Complications
In a small proportion of cases the primary complex progresses to produce more severe
manifestations locally (e.g. caseous pneumonia) or there may be haemotogenous dissemination to
other parts of the body. Thus within a few years of the primary infection, especially during the first
6 months, there is the danger of haemotogenous spread either focal (e.g. bone and joint lesions) or
disseminated (in the form of miliary tuberculosis and tuberculosis meningitis).
Q2. Transmission
Transmission of infection is mainly air-borne by droplets, droplets nuclei and dust; thus it is
enhanced by overcrowding in poorly ventilated accommodation. Infection may also occur by
ingestion especially of contaminated milk and infected meat.
Host Factors
The host response is an important factor in the epidemiology of tuberculosis. A primary infection
may heal, the host acquiring immunity in the process. In some cases the primary lesion progresses
to produce extensive disease locally, or infection may disseminate to produce metastic or military
lesions. Lesions that are apparently healed may subsequently break down with reactivation of
disease. Certain factors such as malnutrition, measles infection and HIV infection, use of
corticosteriods and other debilitating conditions predispose to progression and reactivation of the
disease.

Q3. Individual precautions

Individuals should follow some safety rules to reduce the chance of contracting rabies.

 Vaccinate pets: Find out how often you need to vaccinate your cat, dog, ferret, and other
domestic or farm animals, and keep up the vaccinations.
 Protect small pets: Some pets cannot be vaccinated, so they should be kept in a cage or
inside the house to prevent contact with wild predators.

77
  Keep pets confined: Pets should be safely confined when at home, and supervised when
outside.
 Report strays to the local authorities: Contact local animal control officials or police
departments if you see animals roaming
 Do not approach wild animals: Animals with rabies are likely to be less cautious than usual,
and they may be more likely to approach people.
 Keep bats out of the home: Seal your home to prevent bats from nesting. Call an expert to
remove any bats that are already present.

5.0 Conclusion
Tuberculosis and rabies remain major health problem in the tropical regions, killing millions of
people annually. It requires governmental, non-governmental, community and individual effort to
reduce the incidence of infection.
6.0 Summary
Tuberculosis bacterial disease while rabies is a viral disease. Both of these diseases can be
contracted directly by having contact with infected host. There are many strategies of prevention
and control of these diseases.
7.0 References/Further Readings
Lawrence M., Tiermy Jr., Stephen J., and Machpee M. A., (2002), Current Medical Diagnosis
and Treatment, 41sted. A Lange Publication.
Lucas .A. O. & Gilles H. M. (2003).Short Textbook of Public Health Medicine for the Tropics.
Revised fuorth Edition. Book Power Edition, India.
Stephen J., Machpee M. A. & Padakis (2010), Current Medical Diagnosis and Treatment, 49thed.
A Lange Publication
World Health Organizatio (1994.).Framework for effective Tuberculosis Control WHO/TB/94.
17.9 WHO Geneva.
Crowcroft, N. S., & Thampi, N. (2015, January 14). The prevention and management of rabies.
BMJ. 2015(350), 7827. Retrieved 20th sept, 2019 from
https://www.ncbi.nlm.nih.gov/m/pubmed/25589091/

Human rabies. (2017, August 23). Retrieved 20th sept. 2019 from
https://www.cdc.gov/rabies/location/usa/surveillance/human_rabies.html

Harrist, A., Styczynski, A., Wynn, D. R., Ansari, S., Hopkin, J., Rosado-Santos, H., Musgrave,
K. (2016, July 3). Human rabies – Wyoming and Utah, 2015. Morbidity and Mortality

78
 Weekly (MMWR) 65(21). Retrieved 30st sept.2019 from
https://www.cdc.gov/mmwr/volumes/65/wr/pdfs/mm6521a1.pdf

Other wild animals. (2017, July 5). Retrieved 10 Oct. 2019 from
https://www.cdc.gov/rabies/exposure/animals/other.html

Rabies. (2017, 23 February). Retrieved 10th October, 2019 from

https://www.nhs.uk/conditions/Rabies/Pages/Introduction.aspx

Rabies. (2016, November 4). Retrieved 20th octo.2019 from

https://www.mayoclinic.org/diseases-conditions/rabies/symptoms-causes/syc-20351821

Rabies: Epidemiology and burden of disease. (n.d.). Retrieved 20th Oc t. 2019 from
http://www.who.int/rabies/epidemiology/en/

Rupprect, C. E. (1996). Rhabdoviruses: Rabies virus. Medical Microbiology 4th edition.

Retrieved 13th Oct. 2019 from https://www.ncbi.nlm.nih.gov/books/NBK8618/

What is rabies? (n.d.). Retrieved 16th Oct. 2019 from http://www.who.int/rabies/about/en/

79
Unit 4: Direct Contact (Sexually Transmitted Infection)
CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Meaning of Human Immunodeficiency Virus (HIV)
3.1.1 Differences between HIV and AIDS
3.1.2 Mode of Transmission
3.1.3 Symptoms of HIV/AIDS
3.1.4 Later HIV/AIDS Symptoms
3.1.5 HIV/AIDS Preventive Measures
3.2 Syphilis
3.2.1 Introduction
3.2.2 Causative Agent
3.2.3 Causes
3.2.4 Risk Factors
3.2.5 Symptoms
3.2.6 Manifestation
3.2.7 Prevention
3.3 Gonorrhoea
3.3.1 Causes of Gonorrhoea
3.3.2 Transmission
3.3.3 Signs and Symptoms
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introductions
Direct contact disease transmission occurs when there is physical contact between an infected
person and susceptible person. Sexually transmitted diseases are those disease transmitted through
sexual contact. They are also known as veneral disease. Sexually transmitted diseases are both
health and social problem. They are social problems because their existence and spread are
depended on behaviours. The eradication and prevention of sexually transmitted diseases depend
on moral and ethical standards regarding sexual relationships. Some of these disease include HIV/
80
AIDs, Syphilis and Gonorrhoea. In the previous unit you have learnt about malaria and
onchocerciasis. In this unit you will learn about HIV/AIDs, Syphilis and Gonorrhoea.

I. HIV/AIDS

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:
 differentiate HIV from AIDS
 outline the preventive measures of HIV/AIDS
 discuss the stages of syphilis manifestation
 recognise the prevent strategies of syphilis
 describe the transmission mode of gonorrhoea
 identify the signs and symptoms of gonorrhoea

3.0 Main Content

3.1 Meaning of Human Immunodeficiency Virus

HIV stands for Human Immunodeficiency Virus. It’s a virus that breaks down certain cells in the
immune system (body’s defence against diseases that helps body stay healthy). When HIV
damages the immune system, it’s easier to get really sick and even die from infections that body
could normally fight off. Once the virus gets into the body, it stays in the body for life. There’s no
cure for HIV, but, there are certain medicines that can help the infected person to stay healthy.
HIV medicine lowers or even stops your chances of spreading the virus to other people. Studies
show that using HIV treatment as directed can lower the amount of HIV in the blood so much that
it might not even show up on a test when this happens, you can’t transmit HIV through sex.

3.1.1 Differences between HIV and AIDS

HIV is the virus that causes AIDS. AIDS stands for Acquired Immune Deficiency Syndrome. HIV
and AIDS are not the same thing and people with HIV may not always have AIDS. HIV is the
virus that’s passed from person to person. Over time, HIV destroys an important kind of the cell
in the immune system (called CD4 cells or T cells) that helps protect you from infections. When
you don’t have enough of these CD4 cells, your body can’t fight off infections the way it normally
can.

AIDS is the disease caused by the damage that HIV does to the immune system. Person can have
AIDS when get dangerous infections or have a super low number of CD4 cells. AIDS is the most
serious stage of HIV, and it leads to death over time.

Without treatment, it usually takes about 2 - 10 years for someone with HIV to develop AIDS.
Treatment slows down the damage the virus causes and can help people stay healthy for several
decades.

3.1.2 Mode of Transmission

81
HIV is carried in semen (cum), vaginal fluids, anal mucus, blood, and breast milk. The virus gets
in the body through cuts or sores in the skin, and through mucous membranes (like the inside of
the vagina, rectum, and opening of the penis). HIV can be transmitted through:

 having unprotected vaginal or anal sex

 sharing needles or syringes for shooting drugs, piercings, tattoos, etc.
 getting stuck with a needle that has HIV-infected blood on it
 getting HIV-infected blood, semen (cum), or vaginal fluids into open cuts or sores on the
body

HIV is usually spread through having unprotected sex. Therefore the use of condom during
having sex /having safer sex, not sharing needles can help protect the transmission of HIV. HIV
can also be passed to babies during pregnancy, birth, or breastfeeding. A pregnant woman with
HIV can take medicine to greatly reduce the chance that her baby will get HIV.

Non-transmissible ways

HIV isn’t spread through saliva (spit), so it is not possible to get HIV from kissing, sharing food
or drinks, or using the same fork or spoon. HIV is also not spread through hugging, holding hands,
coughing, or sneezing, cannot be contracted through use of toilet seat. A long time ago, some
people got HIV from infected blood transfusions. But now, giving or getting blood in medical
centers is totally safe as lots of precautions are in place. Doctors, hospitals, and blood donation
centers don’t use needles more than once, and donated blood is tested for HIV and other infections.

For more information follow this: https://www.plannedparenthood.org/learn/stds-hiv-safer-

sex/hiv-aids

3.1.3 Symptoms of HIV/AIDS

The first 2-4 weeks after being infected with HIV, the following symptoms will be noticed
feverish, achy, and sick. These flu-like symptoms are your body’s first reaction to the HIV
infection. During this time, there’s a lot of the virus in the system, so it’s really easy to spread HIV
to other people. The symptoms only last for a few weeks, and then usually don’t have symptoms
again for years. But HIV can be spread to other people — whether or not there are symptoms or
feel sick.

3.1.4 Later HIV/AIDS Symptoms

HIV destroys cells in the immune system called CD4 cells or T cells. Without CD4 cells, the body
has a hard time fighting off diseases. This makes the body more likely to get really sick from
infections that usually wouldn’t hurt the body. Over time, the damage HIV does to the immune
system leads to AIDS.

A person is having AIDS when the body get rare infections (called opportunistic infections) or
types of cancer, or if the body have lost a certain number of CD4 cells. This usually happens about

82
10 years after getting HIV if the person is not on treatment. Treatment can delay or even prevent
ever developing AIDS.

The signs of AIDS include:

 Thrush (a thick, white coating on your tongue or mouth)

 Sore throat
 Bad yeast infections
 Chronic pelvic inflammatory disease
 Getting bad infections a lot
 Feeling really tired, dizzy, and lightheaded
 Headaches
 Losing lots of weight quickly
 Bruising more easily than normal
 Having diarrhoea, fevers, or night sweats for a long time
 Swollen or firm glands in your throat, armpit, or groin
 Deep, dry coughing spells
 Feeling short of breath
 Purplish growths on your skin or inside your mouth
 Bleeding from the mouth, nose, anus, or vagina
 Skin rashes
 Feeling very numb in your hands or feet, losing control of your muscles and reflexes, not
being able to move, and losing strength in your muscles

For more information follow this link:https://www.plannedparenthood.org/learn/stds-hiv-safer-

sex/hiv-aids/what-are-symptoms-hivaids

3.1.5 HIV/AIDS Preventive Measures

Anyone can get HIV, but you can take steps to protect yourself from HIV infection.

 Get tested and know your partner’s HIV status. Talk to your partner about HIV testing
and get tested before you have sex. Use this testing locator from the Centers for Disease
Control and Prevention (CDC) to find an HIV testing location near you.
 Choose less risky sexual behaviours. HIV is mainly spread by having anal or vaginal sex
without a condom or without taking medicines to prevent or treat HIV.
 Use condoms. Use a condom correctly every time you have sex. Read this fact sheet from
CDC on how to use condoms correctly.
 Limit your number of sexual partners. The more partners you have, the more likely you
are to have a partner with poorly controlled HIV or to have a partner with a sexually
transmitted disease (STD). Both of these factors can increase the risk of HIV transmission.
 Get tested and treated for STIs. Insist that your partners get tested and treated, too.
Having an STD can increase your risk of becoming infected with HIV or spreading it to
others.
 Talk to your health care provider about pre-exposure prophylaxis (PrEP). PrEP is an
HIV prevention option for people who don't have HIV but who are at high risk of becoming

83
 infected with HIV. PrEP involves taking a specific HIV medicine every day. For more
information, read the AIDSinfo fact sheet on Pre-Exposure Prophylaxis (PrEP).
 Don't inject drugs. But if you do, use only sterile drug injection equipment and water and
never share your equipment with others.

HIV is spread through contact with blood or sexual fluids (like semen and vaginal fluids), usually
during vaginal and anal sex. So the only 100% certain way to avoid HIV is to not have vaginal or
anal sex. But most people do have sex at some point in their lives, so learning about HIV prevention
and knowing how to have safer sex is important. Using condoms really lowers the risk of getting
HIV. If you are going to have sex, using condoms every single time is the best way to protect
yourself from HIV. There is also a daily pill you can take — called PrEP — that can help prevent
HIV. Some sexual activities are safer than others when it comes to getting HIV. These activities
are “no risk” — they’ve never caused a reported case of HIV:

 masturbating
 touching your partner’s genitals
 rubbing your bodies together (dry humping)
 kissing
 having oral sex with a condom or dental dam
 using clean sex toys

These activities are “lower risk” — they have only caused a few reported cases of HIV (out of
millions):

 "French” or deep kissing (if the person with HIV has sores or bleeding in their mouth)
 vaginal sex with a condom and/or PrEP
 anal sex with a condom and/or PrEP
 oral sex without a condom or dental dam

These activities are “high risk” — millions of people get HIV this way:

 vaginal sex without a condom or PrEP

 anal sex without a condom or PrEP

It’s easier for HIV to get into the body if there sores, cuts, or openings in the skin that semen (cum),
vaginal fluids, or blood may get into. So don not have sex if you have a herpes outbreak or other
infections. Having other STIs makes one more likely to get HIV, so it’s a good idea to get tested
for STIs regularly. There’s no vaccine that protects against HIV, but lots of people are working on
making one. And there are medicines (called PEP and PrEP) that can help prevent HIV.

For more information follow this link:https://aidsinfo.nih.gov/understanding-hiv-aids/fact-

sheets/20/48/the-basics-of-hiv-prevention

3.2 SYPHILIS

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3.2.1 Introduction

Syphilis is a sexually transmitted infection caused by bacteria. The

Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria known as Treponema
pallidum. Syphilis is one of the common sexually transmitted diseases.

Fig 2.11 treponema

3.2.2 Causative Agent

Treponems pallidum (spirochaeta pallida) it is a bacterium which is more serious than gonrrhoea.

3.2.3 Causes

Syphilis is caused when T. pallidum transfers from one person to another during sexual activity.

85
It can also be passed from mother to a fetus during pregnancy, or to an infant during delivery. This
is called congenital syphilis.

It cannot spread through shared contact with objects like doorknobs and toilet seats.

3.2.3 Risk factors

Sexually active people are at risk of contracting syphilis.

Those most at risk include:

 those who have unprotected sex

 men who have sex with men
 those with HIV
 people with numerous sexual partners

Syphilitic sores also increase the risk of contracting HIV.

3.2.5 Symptoms

Syphilis is spread through the sores it causes, known as chancres.

Syphilis is categorized by three stages with varied symptoms associated with each stage.

However, in some cases, there can be no symptoms for several years. Contagious stages include
primary, secondary, and, occasionally, the early latent phase. Tertiary syphilis is not contagious,
but it has the most dangerous symptoms.

3.2.6 Manifestation
The manifestation of syphilis is in stages;
Stage 1 (Primary)
3-6 weeks after infection, a small painless pimple appears on the penis or on the vagina. The
pimples changes into sore known as the primary chancre (skin lesion) the sore may heal
spontaneously (on its own).

Fig. 2.12: Example of a Primary Syphilis Sore.

86
Stage 2 (Secondary)
2-3 weeks from stage 1
1. Fever
2. Skin rash
3. Joint pains
4. Swelling of glands in the neck groin and armpit
5. Spread to the heart, brain and other organs.
6. Person is highly infectious during this stage.

Fig. 2.13: Secondary Rash from Syphilis on Palms of Hands.

Stage 3 (Latent)

The third stage of syphilis is the latent, or hidden, stage. The primary and secondary symptoms
disappear, and there won’t be any noticeable symptoms at this stage. However, the bacteria remain
in the body. This stage could last for years before progressing to tertiary syphilis.

This occurs 5-20 years from time of initial infection.

1. Involment of the eyes, causing blindness
2. Involment of the brain, causing mental problems.
3. Forgetfulness, find it difficult to remember things or promises.
4. Ataxis (walking with unsteady gait).

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Fig. 2.14 Secondary rash from syphilis on torso.

3.2.7 Prevention

Preventive measures to decrease the risk of syphilis, include:

 abstaining from unprotected sexual activities

 long-term mutual monogamy with an uninfected partner
 condom use, although these protect only against genital sores and not those on the body.
 use of a dental dam, or plastic square, during oral sex.
 not sharing sex toys
 avoiding alcohol and drugs that could potentially lead to unsafe sexual practices
 destruction of causative organism
 breaking or destruction of transmission route
 protecting the susceptible host.
 Avoid sharing sex toys.

Having syphilis once does not mean a person is protected from it. Once it is cured, it is possible to
contract it again.

3.3 Gonorrhoea
Gonorrhoea is a sexually transmitted infection (STI) caused by bacteria Neisseria Gonorrhoeae, is
the second most common bacterial STI and results in substantial morbidity and economic cost
worldwide. In women, the infection may occur in the opening of the uterus, also known as the
cervix, and fallopian tubes. In both men and women, the infection may occur in the rectum (the
part of your intestine that ends at the anus), throat and the urethra (the tube that carries urine from
the bladder).
Uncomplicated gonococcal infection commonly manifests as urethritis in men and may cause
mucopurulent cervicitis in women. Rectal and pharyngeal infections in both men and women are

88
largely asymptomatic. Gonococcal infections are often asymptomatic in women; the lack of
discernible symptoms results in unrecognized and untreated infection that may lead to serious
complications, including pelvic inflammatory disease, ectopic pregnancy and infertility. Untreated
urethral infection in men can lead to epididymitis, urethral stricture and infertility. Infants of
mothers with gonococcal infection can contract neonatal conjunctivitis, which may lead to
blindness if left untreated. Neisseria gonorrhoeae can be diagnosed by culture or nucleic acid
amplification tests (NAATs), and by Gram stain in men with urethritis. In settings without
available laboratory diagnostic support, diagnosis is often made clinically, based on the presence
of symptoms such as vaginal and urethral discharge. The treatment of gonococcal infections is
complicated by the rapidly changing antimicrobial susceptibility patterns of N. gonorrhoeae,
raising concerns about the eventual development of untreatable gonococcal infections with serious
sexual and reproductive health consequences.
Uncomplicated gonococcal infection commonly manifests as urethritis in men with symptoms of
urethral discharge and dysuria. On examination, the urethral discharge may range from scanty and
mucoid to copious and purulent. Gonorrhoea is often asymptomatic in women; less than half of
infected women complain of non-specific symptoms such as abnormal vaginal discharge, dysuria,
lower abdominal discomfort and dyspareunia. The most common clinical signs are vaginal
discharge and cervical friability due to mucopurulent cervicitis. Rectal infections in men and
women are largely asymptomatic; occasionally patients complain of rectal and anal pain or
discharge. Pharyngeal infections are mainly asymptomatic, but mild sore throat and pharyngitis
may occur. In the majority of women with gonorrhoea, the lack of discernible symptoms results in
unrecognized and untreated infections. Untreated infections usually resolve spontaneously but
may lead to serious complications such as pelvic inflammatory disease, including endometritis,
salpingitis and tubo-ovarian abscess, which can lead to ectopic pregnancy and infertility. Untreated
urethral infection in men can lead to epididymitis, urethral stricture and infertility. The risk of
complications increases with repeated infection. Infants of mothers with gonococcal infection can
be infected at delivery, resulting in neonatal conjunctivitis manifesting as purulent ocular discharge
and swollen eyelids. Untreated conjunctivitis may lead to scarring and blindness.
3.3.1 Causes of Gonorrhoea
Gonorrhoea is caused by bacteria (tiny living cells) called Neisseria gonorrhea. They can live in
the cervix (entrance to the uterus), the urethra (tube where urine comes out), the rectum (back
passage), the throat and, occasionally, the eyes. Anyone who’s sexually active can easily get and
pass on gonorrhoea. You don’t need to have lots of sexual partners.
3.3.2 Transmission
Gonorrhoea is usually passed from one person to another through sexual contact. You can get the
infection if you come into contact with infected semen (cum or pre-cum) or infected discharge
from the vagina, throat or rectum (back passage).
Gonorrhoea is most commonly spread through:
 vaginal or anal sex without a condom
 oral sex (going down, giving head) without a condom or dam (a latex or plastic square that
covers the anus or vulva)
 Sharing sex toys if you don’t wash them or cover them with a new condom each time
they’re used. If you’re pregnant, it’s possible to pass gonorrhea to the baby
It’s possible for the bacteria to spread from vaginal discharge to the rectum. You don’t need to
have anal sex for this to happen. If gonorrhea is transferred from the genitals to the eye(s) by the

89
fingers it can cause conjunctivitis (an eye infection). This isn’t common. It’s not clear if gonorrhea
can be spread by transferring infected semen or vaginal fluid to another person’s genitals on the
fingers or through rubbing vulvas (female genitals) together. You can’t get gonorrhea from kissing,
hugging, sharing baths or towels, swimming pools, toilet seats or from sharing cups, plates or
cutlery.

3.3.3 Signs and Symptoms

Symptoms may be absent despite an active gonorrheal infection. Symptoms can appear anywhere
from 1-14 days following exposure to the infection.

Men and women experience slightly different symptoms; these can include:

Men:

 white, yellow, or green urethral discharge, resembling pus

 inflammation or swelling of the foreskin
 pain in the testicles or scrotum
 painful or frequent urination
 anal discharge, itching, pain, bleeding, or pain when passing stools
 itching, difficulty swallowing, or swollen neck lymph nodes
 eye pain, light sensitivity, or eye discharge resembling pus
 red, swollen, warm, painful joints

Women:

 painful sexual intercourse

 fever
 yellow or green vaginal discharge
 vulvar swelling
 bleeding in-between periods
 heavier periods
 bleeding after intercourse
 vomiting and abdominal or pelvic pain
 painful or frequent urination
 sore throat, itching, difficulty swallowing, or swollen neck lymph nodes
 eye pain, light sensitivity, and eye discharge resembling pus
 red, swollen, warm, painful joints

Anal gonorrhea signs include:

 itching, bleeding, or pain with passing bowel movements

 anal discharge

An itching or burning sensation in the eyes may be a symptom of conjunctivitis. If infected semen
or fluid comes into contact with the eyes, a person can develop conjunctivitis.

90
Prevention

There are many ways to prevent acquiring or passing on gonorrhea; they include:

 abstinence from sex

 using condoms for vaginal or anal intercourse
 using condoms or dental dams for oral intercourse
 having sexual activity with a mutually monogamous, unaffected partner

Individuals should speak with their doctor if they or their sexual partner have been exposed to
gonorrhea or if they are experiencing any symptoms of infection.

4.0 Self-Assessment Exercise

1. Describe the preventive measures of HIV/AIDS

2. Identify primary and secondary stages of syphilis manifestation
3. Outline the male and female signs and symptoms of gonorrhoea

Answers to Self-Assessment Exercise

Q1. Preventive measures of HIV/AIDS

 .Get tested and knows your partner’s HIV status. Talk to your partner about HIV testing
and get tested before you have sex. Use this testing locator from the Centers for Disease
Control and Prevention (CDC) to find an HIV testing location near you.
 Choose less risky sexual behaviours. HIV is mainly spread by having anal or vaginal sex
without a condom or without taking medicines to prevent or treat HIV.
 Use condoms. Use a condom correctly every time you have sex. Read this fact sheet from
CDC on how to use condoms correctly.
 Limit your number of sexual partners. The more partners you have, the more likely you
are to have a partner with poorly controlled HIV or to have a partner with a sexually
transmitted disease (STD). Both of these factors can increase the risk of HIV transmission.
 Get tested and treated for STDs. Insist that your partners get tested and treated, too.
Having an STD can increase your risk of becoming infected with HIV or spreading it to
others.
 Talk to your health care provider about pre-exposure prophylaxis (PrEP). PrEP is an
HIV prevention option for people who don't have HIV but who are at high risk of becoming
infected with HIV. PrEP involves taking a specific HIV medicine every day. For more
information, read the AIDS fact sheet on Pre-Exposure Prophylaxis (PrEP).
 Don't inject drugs. But if you do, use only sterile drug injection equipment and water and
never share your equipment with others.

Q2. Manifestation
The manifestation of syphilis is in stages;
Stage 1 (primary)

91
3-6 weeks after infection, a small painless pimple appears on the penis or on the vagina. The
pimples changes into sore known as the primary chancre (skin lesion) the sore may heal
spontaneously (on its own).

Example of a primary syphilis sore.

Stage 2 (secondary)
2-3 weeks from stage 1
8 Fever
9 Skin rash
10 Joint pains
11 Swelling of glands in the neck groin and armpit
12 Spread to the heart, brain and other organs.
13 Person is highly infectious during this stage.

Q3. Signs and Symptoms

Symptoms may be absent despite an active gonorrheal infection. Symptoms can appear anywhere
from 1-14 days following exposure to the infection.

Men and women experience slightly different symptoms; these can include:

Men:

 white, yellow, or green urethral discharge, resembling pus

 inflammation or swelling of the foreskin

92
  pain in the testicles or scrotum
 painful or frequent urination
 anal discharge, itching, pain, bleeding, or pain when passing stools
 itching, difficulty swallowing, or swollen neck lymph nodes
 eye pain, light sensitivity, or eye discharge resembling pus
 red, swollen, warm, painful joints

Women:

 painful sexual intercourse

 fever
 yellow or green vaginal discharge
 vulvar swelling
 bleeding in-between periods
 heavier periods
 bleeding after intercourse
 vomiting and abdominal or pelvic pain
 painful or frequent urination
 sore throat, itching, difficulty swallowing, or swollen neck lymph nodes
 eye pain, light sensitivity, and eye discharge resembling pus
 red, swollen, warm, painful joints

5.0 Conclusion

Sexually transmitted infections are diseases that are contracted through unprotected sexual
contacts. STIs has become a public health concern worldwide and cause a wide range of health
problems which include conjunctivitis, blindness, infertility, still birth, abortion and death.
Health education on preventive measures is very essential in prevention of STIs.

6.0 Summary

Sexually transmitted infections are contracted through many ways which include; unprotected sex,
transfusion of unscreened blood, drug abuse, use of infected sharp objects and through mother to
child transmission. Some of sexually transmitted infection diseases are carried in semen, vaginal
fluids, anal mucus, blood, and breast milk. STIs cannot be spread through hugging, holding hands,
coughing, and sneezing or toilet seat. It can be prevented through avoiding multiple sex partners,
use of condom, proper blood screening before transfusion among others.

7.0 References/Further Reading

https://www.plannedparenthood.org/learn/stds-hiv-safer-sex/hiv-aids Retrived 5th may, 2019

https://www.plannedparenthood.org/learn/stds-hiv-safer-sex/hiv-aids/what-are-symptoms-hivai

Retrived 5th may, 2019.

93
Anderson CL, Creswell WH.(1980) School health practice. St. Louis: The CV Mosby Company;
p. 1–185.

Ilika AL, Obionu CO(2002). Personal hygiene practice and school-based health education of
children in Anambra state, Nigeria. Niger Postgrad Med J.;9(2):79–82.

Lucas, A.O and Gilles H.M. (1984) (2nd ed) A short textbook of preventive Medicine
For The Tropics London Hodder and Stoughton chap 5.

Lori S. (2017). Syphilis: What you need to know.

https://www.medicalnewstoday.com/articles/186656.php retrieved 25th October,2019

CDC (2004-2019). Syphilis - CDC Fact Sheet

https://www.cdc.gov/std/syphilis/stdfact-syphilis.htm Retrieved 20th October, 2019.
Newman L, Rowley J, Vander Hoorn S, Wijesooriya NS, Unemo M, Low N (2015). Global
estimates of the prevalence and incidence of four curable sexually transmitted infections
in 2012 based on systematic review and global reporting. PLoS One.; 10(12):e0143304.
doi:10.1371/journal.pone.0143304.

Creighton S, Tenant-Flowers M, Taylor CB, Miller R, Low N. (2003). Co-infection with

gonorrhoea and chlamydia: how much is there and what does it mean? Int J STD AIDS.
14(2):109-13.

Centers for Disease Control and Prevention. Sexually transmitted disease surveillance (2014).
Atlanta (GA): U.S. Department of Health and Human Services; 2015
(https://www.cdc.gov/std/stats14/surv2014-print.pdf, accessed 16/10/ 2016).

Lim RBT, Wong ML, Cook AR, Brun C, Chan RKW, Sen P, Chio M. (2015). Determinants of
chlamydia, gonorrhea, and coinfection in heterosexual adolescents attending the National
Public Sexually Transmitted Infection Clinic in Singapore. Sex Transm Dis. 42: 450-6.

Trecker MA, Dillon J-A R, Lloyd K, Hennink M, Waldner CL. (2015). Demographic and
behavioural characteristics predict bacterial STI reinfection and coinfection among a cross-
sectional sample of laboratory-confirmed gonorrhea cases in a local health region from
Saskatchewan, Canada. Can J Public Health. 106: 17.

Gonorrhea - CDC fact sheet (detailed version). (2015, August 27)

cdc.gov/std/gonorrhea/stdfact-gonorrhea-detailed.htm. Retrieved 21st October, 2019.

cdc.gov/std/stats/sti-estimates-fact-sheet-feb-2013.pdf Retrieved 21st October, 2019

Sexually transmitted infections (STIs). (2015, September)

who.int/mediacentre/factsheets/fs110/en/ Retrieved 21st October, 2019

STDs and HIV – CDC Fact Sheet. (2014, December 16)

cdc.gov/std/hiv/stdfact-std-hiv.htm Retrieved 21st October, 2019
94
Unit 5 Prevention and Control of Communicable Diseases

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Transmission Process and Preventive Measures of Communicable Diseases
3.1.1 Transmission Process
3.1.2 Types Transmission
3.2 Prevention of Communicable Diseases
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction
Prevention is better than cure, to prevent communicable disease it needs multi-approach strategy
which include physician, nurses, public health officers, environmental health officers, health
educators, teachers, students and community members and many other stakeholders. To facilitate
better prevention and control measure of communicable diseases transmission process and type of
transmission need to be understood clearly.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:
 identify the types of communicable diseases transmission
 outline the prevention and control measures of communicable diseases
 describe the ways of communicable disease prevention

3.0 Main Content

3.1 Transmission Process and Preventive Measures of Communicable Diseases
3.1.1 Transmission Process:
Communicable disease transmission is a dynamic process. The process is dependent on the
following: Interaction of the agent (microorganism) the host (person), and the environment
(conditions present).In order for a communicable disease to occur the following factors must be
present:

i. A microorganism of sufficient strength (virulence)

ii. A person who is susceptible (lowered immunity)
iii. An environment supportive to the agent’s transmission

95
3.1.2 Types of Transmission:

Direct Transmission – occurs when an infectious agent enters a receptive portal, i.e., through
direct contact as: touching, kissing, biting, or projecting air droplets by sneezing, talking, spitting,
coughing.

Indirect Transmission – occurs when an infectious agent is deposited on contaminated objects or

materials, i.e., toys, soiled clothes, bedding, cooking or eating utensils, food, water.

a. Enforcing immunization laws and practicing universal precautions/ blood borne pathogen
procedures according to School Board policies, and OSHA regulations.

b. Ongoing health education relating to disease prevention, hygiene measures for students, families
and school personnel.

c. Implementing good hand washing procedures.

d. Implementing case isolation and effective treatment.

For more information follow this linkhttp://www.browardhealthservices.com/communicable-

diseases/communicable-diseases-prevention-and-control/(2019)

3.2 Prevention of Communicable Diseases

According to Division of Communicable Disease Control and Prevention (DCDCP) (2019), the
major components of prevention and control of communicable diseases are:

 Surveillance: collect and analyse data on cases of communicable disease (including but not
limited to HIV, STDs and Hepatitis) and investigate those that pose highest risk to the
public
 Immunization: distribute state-supplied vaccine to health care providers, assess
immunization status of children, and sponsor immunization clinics and maintain a small
computerized registry of immunization records for children from birth to 18 years old
 Public Health Laboratory: provide testing, isolation and identification of harmful
microorganisms that may be present in humans, animals and the environment to aid in the
diagnosis and control of communicable diseases
 Education and Prevention: Provide STD, HIV and Hepatitis education and counselling to
high risk populations and community agencies; screening of high risk individuals and
referral to health care providers for evaluation, treatment and follow-up when appropriate
 Public Health Emergency Preparedness: coordinate with health care and emergency
medical service providers on preventing, detecting, quickly responding to, and recovering
from any type of emergency that impacts your health, particularly those emergencies whose
scale, timing, or unpredictability threatens to overwhelm routine capabilities.

1. Reduce contact rate (case finding &isolation, contact tracing &quarantine, behaviour
change)

96
 2. Reduce infectiousness (treatment, vaccination)
3. Reduce susceptibility (vaccination, immune globulin)
4. Interrupt transmission (infection control)
5. Identify and control reservoir/source (pest/vector control, environmental disinfection)
6. Reduce prevalence of infectious sources (identify and control infectious sources)
7. Reduce duration of infectiousness (treatment, vaccination)
8. Increase herd immunity (vaccination)
(Centre for Infectious Disease Preparedness, 2005).

Mayoclinic.com (2019) opined that, the risk of infecting yourself or others can be decreased
through:

 Wash your hands often. This is especially important before and after preparing food, before
eating and after using the toilet.
 Get vaccinated. Immunization can drastically reduce your chances of contracting many
diseases. Keep your recommended vaccinations up-to-date.
 Use antibiotics sensibly. Take antibiotics only when prescribed. Unless otherwise directed,
or unless you are allergic to them, take all prescribed doses of your antibiotic, even if you
begin to feel better before you have completed the medication.
 Stay at home if you have signs and symptoms of an infection. Don't go to work or class if
you're vomiting, have diarrhoea or are running a fever.
 Be smart about food preparation. Keep counters and other kitchen surfaces clean when
preparing meals. In addition, promptly refrigerate leftovers. Don't let cooked foods remain
at room temperature for an extended period of time.
 Disinfect the 'hot zones' in your residence. These include the kitchen and bathroom — two
rooms that can have a high concentration of bacteria and other infectious agents.
 Practice safer sex. Use condoms. Get tested for sexually transmitted infections (STIs), and
have your partner get tested— or, abstain altogether.
 Don't share personal items. Use your own toothbrush, comb or razor blade. Avoid sharing
drinking glasses or dining utensils.
 Travel wisely. Don't fly when you're ill. With so many people confined to such a small
area, you may infect other passengers in the plane. And your trip won't be comfortable,
either. Depending on where your travels take you, talk to your doctor about any special
immunizations you may need.

4.0 Self-Assessment Exercise

1. Describe the ways in which communicable diseases can be transmitted

2. Identify the prevention techniques of communicable diseases

Answers to Self-Assessment Exercise

1. Transmission Process:

Communicable disease transmission is a dynamic process. The process is dependent on the

following:

97
Interaction of the agent (microorganism) the host (person), and the environment (conditions
present).

In order for a communicable disease to occur the following factors must be present:

i. A microorganism of sufficient strength (virulence)

ii. A person who is susceptible (lowered immunity)
iii. An environment supportive to the agent’s transmission

Types of Transmission:

Direct Transmission – occurs when an infectious agent enters a receptive portal, i.e., through direct
contact as: touching, kissing, biting, or projecting air droplets by sneezing, talking, spitting,
coughing.

Indirect Transmission – occurs when an infectious agent is deposited on contaminated objects or

materials, i.e., toys, soiled clothes, bedding, cooking or eating utensils, food, water.

a. Enforcing immunization laws and practicing universal precautions/ blood borne pathogen
procedures according to School Board policies, and OSHA regulations.

b. Ongoing health education relating to disease prevention, hygiene measures for students, families
and school personnel.

c. Implementing good hand washing procedures.

d. Implementing case isolation and effective treatment.

2. Prevention of Communicable Diseases

 Surveillance: collect and analyse data on cases of communicable disease (including but
not limited to HIV, STIs and Hepatitis) and investigate those that pose highest risk to the
public
 Immunization: distribute state-supplied vaccine to health care providers, assess
immunization status of children, and sponsor immunization clinics and maintain a small
computerized registry of immunization records for children from birth to 18 years old
 Public Health Laboratory: provide testing, isolation and identification of harmful
microorganisms that may be present in humans, animals and the environment to aid in the
diagnosis and control of communicable diseases
 Education and Prevention: Provide STI, HIV and Hepatitis education and counselling to
high risk populations and community agencies; screening of high risk individuals and
referral to health care providers for evaluation, treatment and follow-up when appropriate
 Public Health Emergency Preparedness: coordinate with health care and emergency
medical service providers on preventing, detecting, quickly responding to, and recovering
from any type of emergency that impacts your health, particularly those emergencies whose
scale, timing, or unpredictability threatens to overwhelm routine capabilities.

98
 1. Reduce contact rate (case finding &isolation, contact tracing &quarantine, behaviour
change)
2. Reduce infectiousness (treatment, vaccination)
3. Reduce susceptibility (vaccination, immune globulin)
4. Interrupt transmission (infection control)
5. Identify and control reservoir/source (pest/vector control, environmental disinfection)
6. Reduce prevalence of infectious sources (identify and control infectious sources)
7. Reduce duration of infectiousness (treatment, vaccination)
8. Increase herd immunity (vaccination)

5.0 Conclusion
Communicable diseases are diseases that are easily transmitted from one person to another.
Prevention of these diseases requires multi-approach strategy by all health workers.

6.0 Summary

Tuberculosis, HIV/AIDS, malaria, typhoid fever, hepatitis are some of the common communicable
diseases. Physician, nurses, public health officers, environmental health officers, health educators,
teachers, students and community members and many other stakeholders play very important role
in prevention of communicable diseases. It can be prevented and control through health education,
immunisation, surveillance, laboratory studies and public health emergency preparedness.

7.0 References/Further Reading

Barrett T. (1988). Infection Control Guidelines for Home Health Care. In: Abrutyn, Goldmann,
&Scheckler, eds. Saunders Infection Control Reference Service. Philadelphia, PA: WB
Saunders Company: 81-85.

Centre for Infectious Disease Preparedness. (2005). Understanding strategies to Prevent and
Control Infectious diseases. UC Berkely School of public Health. Retrieved on 31 May 2019
from www.ideady.org.

Division of Communicable Disease Control and Prevention (DCDCP).(2019). Acute

Communicable Disease Control; Disease Surveillance & Epidemiology
Investigation.Alameda County Public Health Department. Oakland: 1-2.

Edemekong, PF&Huang, B.(2019). Epidemiology of Prevention of Communicable Diseases.

StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 3-5.
http://www.browardhealthservices.com/communicable-diseases/communicable-diseases-
prevention-and-control/ (2019)
Mayoclinic.com. (2019).Preventing the Spread of Infectious Diseases. Retrieved on 31 May 2019

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Module 3 Non-Communicable Diseases
In this module, communicable diseases will be discussed in relation to their nature, risk factors,
signs and symptoms, prevention and control measures
Unit 1 Cancer and Obesity
Unit 2 Hypertension
Unit 3 Diabetes
Unit 4 Sickle cell Anaemia and Arthritis
Unit 5 Prevention and Control of Non-Communicable Diseases

Unit 1 Cancer and Obesity

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Cancer
3.1.1 Causes of Cancer
3.1.2 Cancer Prevention and Control
3.1.3 Cancer Screening
3.2 Obesity
3.2.1 Classification
3.2.2 Causes of Obesity
3.2.3 Health Risks Associated with Obesity
3.2.4 Treatment/Prevention
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction
Cancer and obesity affects people irrespective of their ages, sexes and races. Cancer and obesity
are now public health problem worldwide. In this unit you will learn nature, cause, classification
and control and preventive measures of these conditions.
2.0 Intended Learning Outcomes (ILOs)
By the end of this unit, you will be able to:
 identify the causes of cancer.
 describe the prevention and control measures of cancer.
 discuss the causes of obesity.
 outline the health risks associated with obesity.

3.0 Main Content

3.1 Cancer
Cancer may be regarded as a group of diseases characterised by an (i) abnormal growth of cells
(ii) ability to invade adjacent tissues and even distance organs, and (iii) the eventual death of the
affected patient if the tumour has progressed beyond that stage when it can be successfully

100
removed. Cancer can occur at any site or tissue of the body and may involve any type of cells
(WHO, 1997).
The major categories of cancer are: (a) Carcinoma, which arise from epithelial cells lining the
internal surfaces of the various organs (e.g mouth, oesophagus, intestines, uterus) and from the
skin epithelium; (b) Sarcomas, which arise from melanoma cells constituting the various
connective tissues (e.g fibrous tissue, fat and bone); and (c) Lymphomas myeloma and leukaemia
arising from the cells of bone marrow and immune system. .The term “primary tumour” is used to
denote cancer in the organ of origin, while “secondary tumour” denotes cancer that has spread to
regional lymph nodes and distant organ. When cancer cells multiply and reach a critical size, the
cancer is clinically evident as a lump or ulcer localized to the organ of signs of invasion and distant
metastases becomes clinically evident (Park, 2015).
Cancer afflicts all communities worldwide, approximately 10 million peoples are diagnosed with
cancer and more than 6 million die of the disease every year. About 22.4 million persons were
living with cancer in the year 2000. This represents an increase of around 19 percent in incidence
and 18 percent in mortality since 1990. The incidence and mortality worldwide. (WHO, 2013).
The total cancer burden is highest in affluent societies mainly due to a high incidence of tumour
associated with smoking and western lifestyle, i.e. cancer of the lung, coloretum , breast and
prostate. In developing countries, up to 25 percent of tumours are associated with chronic
infections, e.g. hepatitis B (Liver Cancer), human papillomaviruses (Cervical cancer), and
Helicobacter pylor (stomach cancer). In some western countries, cancer mortality rates have
recently started to decline, due to reduction in smoking prevalence, improved early detection and
advances in cancer therapy (Park, 2015).
3.1.2 Causes of Cancer
As with other chronic diseases, cancer has a multifactorial aetiology.
1. Environmental Factors
Environmental factors are generally held responsible for 80 to 90 percent of all human
cancers. (GLOBOCON, 2013). The major environmental factors identified so far include:
(a) Tobacco: Tobacco in its various forms of its usage (e.g smoking, chewing is the major
environmental cause of cancer of the lung, larynx, mouth, pharynx, oesophagus,
bladder, and pancreas)

101
 (b) Alcohol: Excessive intake of alcoholic beverages is associated with oesophageal and
liver cancer. Some recent studies has suggested that beer consumption may be
associated with rectal cancer. It is estimated that alcohol contributed about 3 percent of
all cancer deaths (WHO, 2013).
(c) Dietary Factors: Dietary factors are also related to cancer. Smoke fish is related to
stomach cancer, dietary fibre to intestine to breast cancer. A variety of other dietary
factors such as food additives and contaminants have fallen under suspicious causative
agent.
(d) Occupational Exposures: These include exposure to benzen, arsenic, cadmium,
chromium, vinyl chloride, asbestos, polycyclic hydrocarbons, etc. Many others remain
to be identified. The risk of occupational exposure is considerably increased if the
individuals also smoke cigarette. Occupational exposures are usually reported to
account for 1 to 5 percent of all human cancers.
(e) Microbes and Parasites: An intensive search for a viral origin of human cancers
revealed that hepatitis B and C virus is casually related to hepatocellular carcinoma.
Parasites infections may also increase the risk of cancer, for example, schistosomiasis
in Middle East producing carcinoma of the bladder.
(f) Customs, Habits and Life – Styles: To the above causes must be added customs, habits
and lifestyle of people which may be associated with an increased risk for certain
cancers. The familiar examples are the demonstrated association between smoking and
lung cancer, tobacco and oral cancer etc.

3.1.3 Cancer Prevention and Control

Cancer control consists of a series of measures based on present medical knowledge in the fields
of prevention, detection, diagnosis, treatment, after care and rehabilitation, aimed at reducing
significantly the number of new cases, increasing the number of cures and reducing the invalidism
due to cancer. The basic approach to the control of cancer is through primary and secondary
prevention. It is estimated that at least one-third of all cancers are preventable (WHO, 2014).
1. Primary Prevention
Cancer prevention until recently was mainly concerned with the early diagnosis of the disease
(Secondary prevention), preferably at a precancerous stage. Advancing knowledge has increased

102
understanding of causative factors of some cancers and it is now possible to control these factors
in the general population as well as in particular occupational groups. They include the following:
(a)Control of Tobacco and Alcohol Consumption: Primary prevention offers the greatest hope for
reducing the number of tobacco-induced and alcohol related cancer deaths. It has been estimated
that control of tobacco smoking alone would reduce the total burden of cancer by over a million
cancers each year.
b) Personal Hygiene: Improvements in personal hygiene may lead to decline in the incidence
of certain types of cancer, e.g Cancer cervix.
c) Radiation: Special efforts should be made to reduce the amount of radiation (Including
medical radiation) received by each individual to a minimum without reducing the benefits.
d) Occupational Exposures: The occupational aspects of cancer are frequently neglected.
Measures to protect workers from exposure to industrial carcinogens should be enforced in
industries.
e) Immunisation: In the case of primary liver cancer, immunisation against hepatitis B virus
presents an exciting prospect.
f) Foods, Drugs and Cosmetic: These should be tested for carcinogens.
g) Air Pollution: Control of air pollution is another preventive measure.
h) Treatment of Precancerous Lesions: Early detection and prompt treatment of pre-cancerous
lesions such as cervical tears, intestinal polyposis, warts, chronic gastritis, chronic cervicitis, and
denominate is one of the cornerstones of cancer prevention.
i) Legislation: Legislation has also a role in primary prevention. The solution to cancer
control problems is not to be found in research laboratories. But in legislatures, for example,
legislation to control known environmental carcinogens (e.g. tobacco, alcohol, air pollution) is
inadequate or only moderately enforce in a number of countries.
j) Cancer Education: An important area of primary prevention is cancer education. It should
be directed at “high – risk” groups. The aim of cancer education is to motivate people to seek early
diagnosis and early treatment. Cancer organisations in many countries remind the public of the
early warning signs (“danger signals”) of cancer. These are:
a. A lump or hard area in breast
b. A change in a wart or mole
c. A persistent change in digestive and lowered habits.

103
d. A persistent cough or hoarseness.
e. Excessive loss of blood at the monthly period or loss of blood outside the usual dates.
f. Blood loss from any natural orifice.
g. A swelling or sore that does not get better
(GLOBACAN, 2013).
2. Secondary Prevention
Secondary prevention comprises the following measures:
i) Cancer Registration
Cancer registration provides a base for assessing the magnitude of the problem and for
planning the necessary services. Cancer registries are basically of two types: hospital-based and
population based.
a) Hospital Based Registries: The hospital-based registry includes all patients treated by a
particular institution, whether in-patient or out patients. Registries should be collect the
uniform minimum set of data recommended in the “WHO handbook for Standardized
Cancer Registers”. If there is a long term follow-up of patients, hospital-based registries
can be of considerable value in the evaluation of diagnostic and treatment programmes.
Since hospital population will always be a selected population, the use of these registries
for epidemiological purpose is thus limited.
b) Population Based Registries: A right step is to set up a “hospital-based cancer registry” and
extend the same to a “population-based cancer registry”. The aim is to cover the complete
cancer situation in a given geographic area. The optimum size of base population for a
population based cancer registry is in the range of 2 – 7 million. The data from such
registries alone can provide the incidence rate of cancer and serve as a useful tool for
initiating epidemiological enquiries into causes of cancer, surveillance of time trends, and
planning and evaluation of operational activities in all main areas of cancer control. For
more on cancer registries click on https//www.youtube.com/watch?=oasCxJP3sNw

ii) Early Detection of Cases: Cancer screening is the main weapon for early detection of
cancer at a pre-invasive (in situ) or pre-malignant stage. Effective screening programme have been
developed for cervical cancer, breast cancer and oral cancer. Like primary prevention, early
diagnosis has to be conducted on a large scale. However, it may be possible to increase the
efficiency of screening programmes by focusing on high-risk groups. Clearly, there is no point in

104
detecting cancer at an early stage unless facilities for treatment and aftercare are available. Early
detection programmes will require mobilisation of all available resources and development of a
cancer infrastructure starting at the level of primary health care, ending with complex cancer
centres or institutions at the state or national levels. (GLOBACAN, 2013).
iii) Treatment facilities should be available to all cancer patients: Certain forms of cancer are
amenable to surgical removal, while some others respond favourably to radiation or chemotherapy
or both. Since most of the known methods of treatment have complementary effect on the ultimate
outcome of the patient, multi-modality approach to cancer control has become a standard practice
in cancer centres all over the world. In the developed countries today, cancer treatment is geared
to high technology. For those who are beyond the curable stage, the goal must be to provide pain
relief. A largely neglected problem in cancer care is the management of pain. The WHO has
developed guidelines on relief of cancer pain. “Freedom from cancer pain” is now considered a
right for cancer patients.
3.1.4 Cancer Screening
In the light of present knowledge, early detection and prompt treatment of early cancer and
precancerous conditions provide the best possible protection against cancer for the individual and
the community. Now a good deal of attention is being paid to screening for early detection of
cancer. This approach, that is, cancer screening may be defined as the “search for unrecognized
malignancy by means of rapidly applied tests”.
Cancer screening is possible because: (a) In many instances, malignant disease is proceeded for a
period of months or years by a premalignant lesion, removal of which prevents subsequent
development of cancer: (b) Most cancers begin as localised lesions and if found at this stage a high
rate of cure is obtainable and (c) as much as 75 percent of all cancers occur in body sites that are
accessible (Park, 2013).
3.2 Obesity

Obesity is defined as abnormal or excessive fat accumulation that presents a risk to health. A
crude population measure of obesity is the body mass index (BMI), a person’s weight (in
kilograms) divided by the square of his or her height (in metres). A person with a BMI of 30 or
more is generally considered obese. A person with a BMI equal to or more than 25 is considered
overweight.
Fig 3.2 obesity

105
Obesity is a condition in which excess body fat has accumulated to an extent that it may have a
negative effect on health and is most commonly caused by a combination of excessive food
intake, lack of physical activity, and genetic susceptibility World Health Organization (WHO,
2016). Obesity is major risk factors for a number of chronic diseases, including diabetes,
cardiovascular diseases and cancer. Once considered a problem only in high income countries,
overweight and obesity are now dramatically on the rise in low- and middle-income countries,
particularly in urban settings. Follow this link for more information
https://www.who.int/topics/obesity/en/

106
Fig. 3.3:
In some developed countries obesity has reached epidemic proportions.
3.2.1 Classification
Obesity is classified according to level of Body Mass Index (BMI):
 Any BMI ≥ 35 or 40 kg/m2 is severe obesity.
 A BMI of ≥ 35 kg/m2 and experiencing obesity-related health conditions or ≥40–
44.9 kg/m2 is morbid obesity.
 A BMI of ≥ 45 or 50 kg/m2 is super obesity

3.2.2 Causes of Obesity

The balance between calorie intake and energy expenditure determines a person's weight. If a
person eats more calories than he or she burns (metabolizes), the person gains weight (the body
will store the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he
or she will lose weight. Therefore, the most common causes of obesity are overeating and physical
inactivity and ultimately, body weight is the result of genetics, metabolism, environment, behavior,
and culture (WHO, 2016).

107
To Dibaise and Foxx-Orenstein (2013) the following are the common causes of obesity:

 Physical inactivity: Sedentary people burn fewer calories than people who are active. The
National Health and Nutrition Examination Survey (NHANES) showed a strong
correlations between physical inactivity and weight gain in both sexes.
 Overeating: Overeating leads to weight gain, especially if the diet is high in fat. Foods high
in fat or sugar (for example, fast food, fried food, and sweets) have high energy density
(foods that have a lot of calories in a small amount of food). Epidemiologic studies have
shown that diets high in fat contribute to weight gain.
 Genetics: A person is more likely to develop obesity if one or both parents are obese.
Genetics also affect hormones involved in fat regulation. For example, one genetic cause
of obesity is leptin deficiency. Leptin is a hormone produced in fat cells and in the placenta.
Leptin controls weight by signaling the brain to eat less when body fat stores are too high.
If, for some reason, the body cannot produce enough leptin or leptin cannot signal the brain
to eat less, this control is lost, and obesity occurs. The role of leptin replacement as a
treatment for obesity is under exploration.
 A diet high in simple carbohydrates: The role of carbohydrates in weight gain is not clear.
Carbohydrates increase blood glucose levels, which in turn stimulate insulin release by the
pancreas, and insulin promotes the growth of fat tissue and can cause weight gain. Some
scientists believe that simple carbohydrates (sugars, fructose, desserts, soft drinks, beer,
wine, etc.) contribute to weight gain because they are more rapidly absorbed into the
bloodstream than complex carbohydrates (pasta, brown rice, grains, vegetables, raw fruits,
etc.) and thus cause a more pronounced insulin release after meals than complex
carbohydrates. This higher insulin release, some scientists believe, contributes to weight
gain.
 Frequency of eating: The relationship between frequency of eating (how often you eat) and
weight is somewhat controversial. There are many reports of overweight people eating less
often than people with normal weight. Scientists have observed that people who eat small
meals four or five times daily, have lower cholesterol levels and lower and/or more stable
blood sugar levels than people who eat less frequently (two or three large meals daily). One

108
 possible explanation is that small frequent meals produce stable insulin levels, whereas
large meals cause large spikes of insulin after meals.
 Psychological factors: For some people, emotions influence eating habits. Many people eat
excessively in response to emotions such as boredom, sadness, stress, or anger. While most
overweight people have no more psychological disturbances than normal weight people,
about 30% of the people who seek treatment for serious weight problems have difficulties
with binge eating.
 Diseases such as hypothyroidism, insulin resistance, polycystic ovary syndrome, and
Cushing's syndrome are also contributors to obesity. Some diseases, such as Prader-Willi
syndrome, can lead to obesity.
 Social issues: There is a link between social issues and obesity. Lack of money to purchase
healthy foods or lack of safe places to walk or exercise can increase the risk of obesity.

Keith (2006) identified ten other possible contributors to the recent increase of obesity: (1)
insufficient sleep, (2) endocrine disruptors (environmental pollutants that interfere with lipid
metabolism), (3) decreased variability in ambient temperature, (4) decreased rates of smoking,
because smoking suppresses appetite, (5) increased use of medications that can cause weight gain
(e.g., atypical antipsychotics), (6) proportional increases in ethnic and age groups that tend to be
heavier, (7) pregnancy at a later age (which may cause susceptibility to obesity in children), (8)
epigenetic risk factors passed on generationally, (9) natural selection for higher BMI, and (10)
assortative mating leading to increased concentration of obesity risk factors (this would increase
the number of obese people by increasing population variance in weight).

109
Fig. 3.4: Surprising Reasons for Weight Gain See Slideshow
Other factors associated with obesity
 Ethnicity. Ethnicity factors may influence the age of onset and the rapidity of weight gain.
African-American women and Hispanic women tend to experience weight gain earlier in
life than Caucasians and Asians, and age-adjusted obesity rates are higher in these groups.
Non-Hispanic black men and Hispanic men have a higher obesity rate then non-Hispanic
white men, but the difference in prevalence is significantly less than in women.
 Childhood weight. A person's weight during childhood, the teenage years, and early
adulthood may also influence the development of adult obesity. Therefore, decreasing the
prevalence of childhood obesity is one of the areas to focus on in the fight against obesity.
For example,
o being mildly overweight in the early 20s was linked to a substantial incidence of
obesity by age 35;
o being overweight during older childhood is highly predictive of adult obesity,
especially if a parent is also obese;
o being overweight during the teenage years is even a greater predictor of adult
obesity.
 Hormones. Women tend to gain weight especially during certain events such as
pregnancy, menopause, and in some cases, with the use of oral contraceptives. However,

110
 with the availability of the lower-dose estrogen pills, weight gain has not been as great a
risk.

3.2.3 Health Risks Associated with Obesity

Obesity also increases the risk of developing a number of chronic diseases, including the
following:
 Insulin resistance: Insulin is necessary for the transport of blood glucose (sugar) into the
cells of muscle and fat (which the body uses for energy). By transporting glucose into cells,
insulin keeps the blood glucose levels in the normal range. Insulin resistance (IR) is the
condition whereby there is diminished effectiveness of insulin in transporting glucose
(sugar) into cells. Fat cells are more insulin resistant than muscle cells; therefore, one
important cause of insulin resistance is obesity. The pancreas initially responds to insulin
resistance by producing more insulin. As long as the pancreas can produce enough insulin
to overcome this resistance, blood glucose levels remain normal. This insulin resistance
state (characterized by normal blood glucose levels and high insulin levels) can last for
years. Once the pancreas can no longer keep up with producing high levels of insulin, blood
glucose levels begin to rise, resulting in type 2 diabetes, thus insulin resistance is a pre-
diabetes condition.
 Type 2 (adult-onset) diabetes: The risk of type 2 diabetes increases with the degree and
duration of obesity. Type 2 diabetes is associated with central obesity; a person with central
obesity has excess fat around his/her waist (apple-shaped figure).
 High blood pressure (hypertension): Hypertension is common among obese adults. A
Norwegian study showed that weight gain tended to increase blood pressure in women
more significantly than in men.
 High cholesterol (hypercholesterolemia)
 Stroke (cerebrovascular accident or CVA)
 Heart attack: A prospective study found that the risk of developing coronary artery disease
increased three to four times in women who had a BMI greater than 29. A Finnish study
showed that for every 1 kilogram (2.2 pounds) increase in body weight, the risk of death
from coronary artery disease increased by 1%. In patients who have already had a heart
attack, obesity is associated with an increased likelihood of a second heart attack.

111
  Congestive heart failure
 Cancer: Obesity is a risk factor for cancer of the colon in men and women, cancer of the
rectum and prostate in men, and cancer of the gallbladder and uterus in women. Gallstones
 Gout and gouty arthritis
 Osteoarthritis (degenerative arthritis) of the knees, hips, and the lower back
 Sleep apnea
3.3.4 Treatment/Prevention
The main treatment for obesity consists of dieting and physical exercise (US Department of Health
and Human Services, 2017). Dieting, as part of a lifestyle change, produces sustained weight loss,
despite slow weight regain over time (Jensen, 2014). Intensive behavioral interventions combining
both dietary changes and exercise are recommended (US Department of Health and Human
Services, 2017).

Several diets are effective. In the short-term low carbohydrate diets appear better than low fat diets
for weight loss, but in the long term; however, all types of low-carbohydrate and low-fat diets
appear equally beneficial (Johnston, Kanters, Bandayrel, Wu, Naji, Siemieniuk, Ball, Busse,
Thorlund, Guyatt, Jansen, Mills, 2014).

Decreased intake of sweet drinks is also related to weight-loss and success rates of long-term
weight loss maintenance with lifestyle changes are low, ranging from 2–20% (Wing & Phelan,
2005).

The role of physical activity and exercise in obesity?

Physical activity and exercise help burn calories. The amount of calories burned depends on the
type, duration, and intensity of the activity. It also depends on the weight of the person.

However regular exercise is an important part of a healthy lifestyle to maintain a healthy weight
for the long term. Another advantage of regular exercise as part of a weight-loss program is a
greater loss of body fat versus lean muscle compared to those who diet alone. National Health and
Examination Survey (NHANES I)

112
Other benefits of exercise include

 improved blood sugar control and increased insulin sensitivity (decreased insulin
resistance),
 reduced triglyceride levels and increased "good" HDL cholesterol levels,
 lowered blood pressure,
 a reduction in abdominal fat,
 reduced risk of heart disease,
 release of endorphins that make people feel good.

General exercise recommendations

 Perform 20-30 minutes of moderate exercise five to seven days a week, preferably daily.
Types of exercise include stationary bicycling, walking or jogging on a treadmill, stair
climbing machines, jogging, and swimming.
 Exercise can be broken up into smaller 10-minute sessions.
 Start slowly and progress gradually to avoid injury, excessive soreness, or fatigue. Over
time, build up to 30-60 minutes of moderate to vigorous exercise every day.
 People are never too old to start exercising. Even frail, elderly individuals (70-90 years of
age) can improve their strength and balance.

Exercise precautions
The following people should consult a doctor before vigorous exercise:

 Men over age 40 or women over age 50

 Individuals with heart or lung disease, asthma, arthritis, or osteoporosis
 Individuals who experience chest pressure or pain with exertion, or who develop fatigue or
shortness of breath easily
 Individuals with conditions or lifestyle factors that increase their risk of developing
coronary heart disease, such as high blood pressure, diabetes, cigarette smoking, high blood
cholesterol, or having family members with early onset heart attacks and coronary heart
disease
 A patient who is obese.

113
4.0 Self-Assessment Exercise
1. Describe the causes of cancer
2. Outline the prevention and control measures of cancer
3. State the classification of obesity based on BMI.
4. What are the causes of obesity?

Answers to Self-Assessment Exercise

1. Causes of Cancer
As with other chronic diseases, cancer has a multifactorial aetiology.
1. Environmental Factors
Environmental factors are generally held responsible for 80 to 90 percent of all human
cancers. The major environmental factors identified so far include:
(a) Tobacco: Tobacco various forms of its usage (e.g smoking, chewing is the major
environmental cause of cancer of the lung, larynx, mouth, pharynx, oesophagus,
bladder, and pancreas)
(b) Alcohol: Excessive intake of alcoholic beverages is associated with oesophageal and
liver cancer. Some recent studies has suggested that beer consumption may be
associated with rectal cancer. It is estimated that alcohol contributed about 3 percent of
all cancer deaths.
(c) Dietary Factors: Dietary factors are also related to cancer. Smoke fish is related to
stomach cancer, dietary fibre to intestine to breast cancer. A variety of other dietary
factors such as food additives and contaminants have fallen under suspicious causative
agent.
(d) Occupational Exposures: These include exposure to benzen, arsenic, cadmium,
chromium, vinyl chloride, asbestos, polycyclic hydrocarbons, etc. Many others remain
to be identified. The risk of occupational exposure is considerably increased if the
individuals also smoke cigarette. Occupational exposures are usually reported to
account for 1 to 5 percent of all human cancers.
(e) Microbes and Parasites: An intensive search for a viral origin of human cancers
revealed that hepatitis B and C virus is casually related to hepatocellular
carcinoma.Parasites infections may also increase the risk of cancer, for example,
schistosomiasis in Middle East producing carcinoma of the bladder.

114
 (f) Customs, Habits and Lifestyles: To the above causes must be added customs, habits
and lifestyle of people which may be associated with an increase risk for certain
cancers. The familiar examples are the demonstrated association between smoking and
lung cancer, tobacco and oral cancer etc.

2. Cancer Prevention and Control

Cancer control consists of a series of measures based on present medical knowledge in the fields
of prevention, detection, diagnosis, treatment, after care and rehabilitation, aimed at reducing
significantly the number of new cases, increasing the number of cures and reducing the invalidism
due to cancer. The basic approach to the control of cancer is through primary and secondary
prevention. It is estimated that at least one-third of all cancers are preventable.
1. Primary Prevention
Cancer prevention until recently was mainly concerned with the early diagnosis of the disease
(Secondary prevention), preferably at a precancerous stage. Advancing knowledge has increased
understanding of causative factors of some cancers and it is now possible to control these factors
in the general population as well as in particular occupational groups. They include the following:
a) Control of Tobacco and Alcohol Consumption: Primary prevention offers the greatest hope for
reducing the number of tobacco-induced and alcohol related cancer deaths. It has been estimated
that control of tobacco smoking alone would reduce the total burden of cancer by over a million
cancers each year.
b) Personal Hygiene: Improvements in personal hygiene may lead to decline in the incidence
of certain types of cancer, e.g cancer of cervix.
c) Radiation: Special efforts should be made to reduce the amount of radiation (Including
medical radiation) received by each individual to a minimum without reducing the benefits.
d) Occupational Exposures: The occupational aspects of cancer are frequently neglected.
Measures to protect workers from exposure to industrial carcinogens should be enforced in
industries.
e) Immunisation: In the case of primary liver cancer, immunisation against hepatitis B virus
presents an exciting prospect.
f) Foods, Drugs and Cosmetic: These should be tested for carcinogens.
g) Air Pollution: Control of air pollution is another preventive measure.

115
h) Treatment of Precancerous Lesions: Early detection and prompt treatment of precancerous
lesions such as cervical tears, intestinal polyposis, warts, chronic gastritis, chronic cervicitis , and
denominate is one of the cornerstones of cancer prevention.
i) Legislation: Legislation has also a role in primary prevention. The solution to cancer
control problems is not to be found in research laboratories. But in legislatures. For example,
legislation to control known environmental carcinogens (e.g tobacco, alcohol, air pollution) is
inadequate or only moderately enforce in a number of countries.
j) Cancer Education: An important area of primary prevention is cancer education. It should
be directed at “high – risk” groups. The aim of cancer education is to motivates people to seek
early diagnosis and early treatment. Cancer organisations in many countries remind the public of
the early warning signs (“danger signals”) of cancer. These are:
a. A lump or hard area in breast
b. A change in a wart or mole
c. A persistent change in digestive and bowel habits.
d. A persistent cough or hoarseness.
e. Excessive loss of blood at the monthly period or loss of blood outside the usual dates.
f. Blood loss from any natural orifice.
g. A swelling or sore that does not get better
3. Classification
Obesity is classified according to level of Body Mass Index (BMI):
 Any BMI ≥ 35 or 40 kg/m2 is severe obesity.
 A BMI of ≥ 35 kg/m2 and experiencing obesity-related health conditions or ≥40–
44.9 kg/m2 is morbid obesity.
 A BMI of ≥ 45 or 50 kg/m2 is super obesity

4. Causes of Obesity

 Physical inactivity: Sedentary people burn fewer calories than people who are active. The
National Health and Nutrition Examination Survey (NHANES) showed a strong
correlations between physical inactivity and weight gain in both sexes.
 Overeating: Overeating leads to weight gain, especially if the diet is high in fat. Foods high
in fat or sugar (for example, fast food, fried food, and sweets) have high energy density

116
 (foods that have a lot of calories in a small amount of food). Epidemiologic studies have
shown that diets high in fat contribute to weight gain.
 Genetics: A person is more likely to develop obesity if one or both parents are obese.
Genetics also affect hormones involved in fat regulation. For example, one genetic cause
of obesity is leptin deficiency. Leptin is a hormone produced in fat cells and in the placenta.
Leptin controls weight by signaling the brain to eat less when body fat stores are too high.
If, for some reason, the body cannot produce enough leptin or leptin cannot signal the brain
to eat less, this control is lost, and obesity occurs. The role of leptin replacement as a
treatment for obesity is under exploration.
 A diet high in simple carbohydrates: The role of carbohydrates in weight gain is not clear.
Carbohydrates increase blood glucose levels, which in turn stimulate insulin release by the
pancreas, and insulin promotes the growth of fat tissue and can cause weight gain. Some
scientists believe that simple carbohydrates (sugars, fructose, desserts, soft drinks, beer,
wine, etc.) contribute to weight gain because they are more rapidly absorbed into the
bloodstream than complex carbohydrates (pasta, brown rice, grains, vegetables, raw fruits,
etc.) and thus cause a more pronounced insulin release after meals than complex
carbohydrates. This higher insulin release, some scientists believe, contributes to weight
gain.
 Frequency of eating: The relationship between frequency of eating (how often you eat) and
weight is somewhat controversial. There are many reports of overweight people eating less
often than people with normal weight. Scientists have observed that people who eat small
meals four or five times daily, have lower cholesterol levels and lower and/or more stable
blood sugar levels than people who eat less frequently (two or three large meals daily). One
possible explanation is that small frequent meals produce stable insulin levels, whereas
large meals cause large spikes of insulin after meals.
 Psychological factors: For some people, emotions influence eating habits. Many people eat
excessively in response to emotions such as boredom, sadness, stress, or anger. While most
overweight people have no more psychological disturbances than normal weight people,
about 30% of the people who seek treatment for serious weight problems have difficulties
with binge eating.

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  Diseases such as hypothyroidism, insulin resistance, polycystic ovary syndrome, and
Cushing's syndrome are also contributors to obesity. Some diseases, such as Prader- Willi
syndrome, can lead to obesity.
 Social issues: There is a link between social issues and obesity. Lack of money to purchase
healthy foods or lack of safe places to walk or exercise can increase the risk of obesity.

5.0 Conclusion

The main objective is to identify the causes of cancer realise the prevention and control measures
of cancer disease. Cancer is regarded as a group of diseases characterised by an abnormal growth
of cells. Cancer can occur at any site or tissue of the body and may involve any type of cells.
Cancer affects all individuals worldwide, many people are diagnosed with cancer and many die of
the disease every year.
Conclusively, obesity is a condition in which excess accumulation of body fat to an extent that it
may have serious health effect. The condition is not only associated with excessive food intake but
include lack of physical activity, and genetic susceptibility.

6.0 Summary
In this unit, we have discussed cancer as a disease, causes of cancer disease as tobacco smoking,
alcohol taking, dietary factors, occupational exposure, customs, habits and life style. Cancer
prevention and control was also examined which included primary prevention and secondary
prevention.

Obesity is major risk factors for chronic metabolic, cardiovascular diseases and cancer. It is
problem that cut across high income and low income countries, overweight and obesity are now at
increase at an alarming rate particularly in urban settings.

7.0 References/ Further reading

GLOBOCAN(2013). World fact sheet, section of cancer information, International Agency for
Research on cancer, Lyon France.
Park K. (2015). Textbook of Preventive and Social Medicine.(21st ed.) BanardidAsbhanot
India. Publishers Jabalpur,
World Health Organizatio (2014). World Cancer Fact sheet, Cancer Research UK,.
World Health Organizatio (1997). The World Health Report of the Director General WHO.
World Health Organizatio (2013).Press release no 223, 12 Dec. 2013, Latest WorldCancers
satistics.

118
Afshin A, Forouzanfar MH, Reitsma MB, Sur P, Estep K, Lee A( 2017). "Health Effects of
Overweight and Obesity in 195 Countries over 25 Years". The New England Journal of
Medicine. 377 (1): 13–27. doi:10.1056/NEJMoa1614362.

Arnett, Donna K.; Blumenthal, Roger S.; Albert, Michelle A.; Buroker, Andrew B.; Goldberger,
et’al. (2019). "2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular
Disease". Circulation. doi:10.1161/CIR.0000000000000678. Retrieved 30 September 2019.

Dibaise JK, Foxx-Orenstein AE (July 2013). "Role of the gastroenterologist in managing obesity".
Expert Review of Gastroenterology & Hepatology (Review). 7 (5): 439–51.
doi:10.1586/17474124.2013.811061.

Encyclopedia of Mental Health (2 ed.). DC Washington Academic Press. 2015. p. 158.

ISBN 9780123977533

Haslam DW, James WP (October 2005). "Obesity". Lancet (Review). 366 (9492): 1197–209.
doi:10.1016/S0140-6736(05)67483-1.

Heymsfield SB, Wadden TA (January 2017). "Mechanisms, Pathophysiology, and Management

of Obesity". The New England Journal of Medicine. 376 (3): 254–266.
doi:10.1056/NEJMra1514009.

Jensen, MD; Ryan, DH; Apovian, CM; Ard, JD; Comuzzie, AG; Donato, KA; Hu, FB; Hubbard,
VS; Jakicic,et’al . (2014). American College of Cardiology/American Heart Association
Task Force on Practice, Guidelines, Obesity, Society. "2013 AHA/ACC/TOS guideline
for the management of overweight and obesity in adults: a report of the American College
of Cardiology/American Heart Association Task Force on Practice Guidelines and The
Obesity Society". Circulation. 129 (25 Suppl 2): S102–38.
doi:10.1161/01.cir.0000437739.71477.ee

Johnston BC, Kanters S, Bandayrel K, Wu P, Naji F, Siemieniuk RA, Ball GD, Busse JW,
Thorlund K, Guyatt G, Jansen JP, Mills EJ (September 2014). "Comparison of weight
loss among named diet programs in overweight and obese adults: a meta-analysis".
JAMA. 312 (9): 923–33. doi:10.1001/jama.2014.10397.

Keith SW, Redden DT, Katzmarzyk PT, Boggiano MM, Hanlon EC, Benca RM, Ruden D, et’al.
(2006). "Putative contributors to the secular increase in obesity: exploring the roads less
travelled". International Journal of Obesity (Review). 30 (11): 1585–94.
doi:10.1038/sj.ijo.0803326.

LeFevre ML (October 2014). "Behavioral counseling to promote a healthful diet and physical
activity for cardiovascular disease prevention in adults with cardiovascular risk factors:
U.S. Preventive Services Task Force Recommendation Statement". Annals of Internal
Medicine. 161 (8): 587–93. doi:10.7326/M14-1796.

Obesity and overweight Fact sheet N°311". WHO. January 2015. Retrieved 20 Sept. 2019

119
 Oxford Handbook of Medical Sciences (2nd ed.). England Oxford: OUP Oxford. 2011.
p. 180. ISBN 9780191652295.
Pollack A (18 June 2013). "A.M.A. Recognizes Obesity as a Disease". New York Times. Archived
from the original on 24 June 2013.

US Department of Health and Human Services. (2017). "2015–2020 Dietary Guidelines for
Americans - health.gov". health.gov. Skyhorse Publishing Inc. Retrieved 30 September
2019.

Weinstock, Matthew (21 June 2013). "The Facts About Obesity". H&HN. American Hospital
Association. Retrieved 24 Sept. 2019

Wing RR, Phelan S (July 2005). "Long-term weight loss maintenance". The American Journal of
Clinical Nutrition (Review). 82 (1 Suppl): 222S–225S. doi:10.1093/ajcn/82.1.222S.

Woodhouse R (2008). Obesity in art: a brief overview. Frontiers of Hormone Research. 36.
pp. 271–86. doi:10.1159/000115370. ISBN 978-3-8055-8429-6.

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Unit 2 Hypertension
CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Hypertension
3.2 Classification of Blood Pressure Measurement
3.3 Risk Factors for Hypertension
3.4 Prevention of Hypertension
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

In the previous unit you have learnt on the nature, cause, classification and control and preventive
measures of these conditions. And in this unit you will learn on definition of hypertension,
classification of blood pressure, risk factors of hypertension and prevention and control measures
of hypertension.

2.0 Intended Learning Outcomes (s)

By the end of this unit, you will be able to:
 define hypertension
 identify the classification of high blood pressure measurement.
 outline the risk factors of hypertension
 describe the prevention and control measures of hypertension

3.0 Main Content

3.1 Hypertension

Hypertension is a condition in which the force of the blood against the artery walls is too high
otherwise called high blood pressure. Hypertension is a chronic condition of concern due to its
role in the causation of coronary heart diseases, stroke and other vascular complication. It is the
commonest cardiovascular disorder, posing a major public health challenge to population in socio-
economic and epidemiological transition. It is one of the major risk factors for cardiovascular
mortality, which accounts for 20-50 percent of all deaths. There is also a direct relation between
cardiovascular risk and blood pressure; the higher the blood pressure, the higher the risk of both
stroke and coronary events (Park, 2015).

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3.1 Classification of Blood Pressure Measurement
Category Systolic Blood Pressure (mm Diastolic Blood Pressure (mm
of Hg) of Hg)
Normal <130 <85
High Normal 130 – 139 85 – 90
Hypertension
Stage 1 (Mild) 140 – 159 90 – 99
Stage 2 (Moderate) 160 – 179 100 – 109
Stage 3 (Severe) >180 > 110

When systolic and diastolic blood pressure fall into different categories, the higher category should
be selected to classify the individual’s blood pressure. “Isolated systolic hypertension” is defined
as a systolic blood pressure of 140mm of Hg or more and a diastolic blood pressure of less than
90mm of Hg.
Fig 3.5 measurement of blood pressure

122
123
3.3 Risk Factors for Hypertension
Hypertension is not only one of the major risk factors for most forms of cardiovascular diseases,
but that it is a condition with its own risk factors. A World Health Organization (WHO, 1996)
Scientific Group has recently reviewed the risk factors for essential hypertension. These may be
classified as:
1. Non-Modifiable Risk Factors
a) Age: Blood pressure rises with age in both sexes and the risk is greater in those with higher
initial blood pressure. Age probably represents an accumulation of environmental influence and
the effects of genetically programmed senescence in body systems. Some populations have now
been identified whose mean blood pressure does not rise with age. These communities are for the
most part primitive societies with calorie and often salt intakes at low level.
b) Sex: Early in life there is little evidence of a difference in blood pressure between the sexes.
However, at adolescence, men display a higher average level. This difference is most evident in
young and middle aged adults. Late in life the difference narrows and the pattern may even be
reversed. Post-menopausal changes in women may be the contributory factor for this change.
c) Genetic Factors: There is considerable evidence that blood pressure levels are determined
in part by genetic factors, and that the inheritance is polygenic. Family studies have shown that the
children of two normotensive parents have 3 percent possibility of developing hypertension,
whereas this possibility is 45 percent in children of two hypertensive parents. Blood pressure levels
among first degree adult relatives have also been noted to be statistically significant.
d) Ethnicity: Population studies have consistently revealed higher blood pressure levels in
black communities than other ethnic groups.
2. Modifiable Risk Factors
a) Obesity: Epidemiological observations has identified obesity as a risk factor for hypertension.
The greater the weight gain, the greater the risk of high blood pressure. Data also indicate that
when people with high blood pressure lose weight, their blood pressure generally decrease.
b) Salt Intake: There is an increasingly body of evidence to the effect that a high salt intake (i.e 7
– 8g per day) increase blood pressure proportionately. Low sodium intake has been found to lower
the blood pressure. Besides sodium, there are other mineral elements such as potassium which are
determinants of blood pressure. Potassium antagonises the biological effects of sodium and thereby
reduces blood pressure. Potassium supplements have been found to lower blood pressure of mild

124
to moderate hypertensive. Calcium, cadmium and magnesium have also been suggested as of
importance reducing blood pressure levels.
c) Saturated Fat: The evidence suggest that saturated fat raises blood pressure as well as serum
cholesterol.
d) Dietary Fibre: Several studies indicate that the risk of hypertension is inversely related to the
consumption of dietary fibre. Most fibres reduce plasma and total cholesterol.
E Alcohol: High alcohol intake is associated with an increased risk of high blood pressure. It
appears that alcohol consumption raises systolic pressure more than the diastolic. But the finding
that blood pressure returns to normal with abstinence suggests that alcohol-induced elevation may
not be fixed, and do not necessarily lead to sustained blood pressure elevation.
g) Physical Activity: Physical activity by reducing body weight may have an indirect effect on
blood pressure.
h) Environmental Stress: The term hypertension itself implies a disorder initiated by tension or
stress. It is an accepted fact that psychosocial factors operate through mental processes,
consciously or unconsciously, to produce hypertension.
i) Socio–Economic Status: In countries that are in post transitional stage of economic and
epidemiological change, consistently higher levels of blood pressure have been noted in lower
socio-economic groups. This inverse relation has been noted with levels of education, income and
occupation, a higher prevalence of hypertension have been noted in upper socio-economic groups.
3.4 Prevention of Hypertension
The low prevalence of hypertension in some communities indicates that hypertension is potentially
preventable. The WHO recommended the following approaches in the prevention of hypertension
(Park, 2015).
1. Primary Prevention
Although control of hypertension can be successfully achieved by medication (Secondary
Prevention) the ultimate goal in general is primary prevention. Primary prevention has been
defined as “all measures to reduce the incidence of diseases in population by reducing the risk of
onset”. The earlier the prevention starts, the more likely it is to be effective. In connection with
primary prevention, terms such as “population strategy” and “high-risk strategy” have become
established. The WHO has recommended these approaches in the prevention of hypertension. Both
the approaches are complementary.

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Population Strategy
The population approach is directed at the whole population, irrespective of individual risks levels.
The concept of population approach is based on the fact that even a small reduction in the – average
blood pressure of a population would produce a large reduction in the incidence of cardiovascular
complications such as stroke and CHD. The goal of the population approach is to shift the
community distribution of blood pressure towards lower levels or “biological normality”. This
involves a multifactorial approach, based on the following non-pharmacotherapeutic interventions:
a) Nutrition: Dietary changes are of paramount importance. This comprise: (i) reduction of salt
intake to an average of not more than 5gm per day (ii) moderate fat intake (iii) the avoidance of a
high alcohol intake, and (iv) restriction of energy intake appropriate to body needs.
b) Weight Reduction: The prevention and correction of overweight/obesity (Body Mass index
greater than 25) is a prudent way of reducing the risk of hypertension and indirectly CHD: It goes
with dietary changes.
c) Exercise Promotion: The evidence that regular physical activity leads to a fall in body weight,
blood lipids and blood pressure goes to suggest that regular physical activity should be encouraged
as part of the strategy for risk-factor control.
d) Behavioural Changes: Reduction of stress and smoking. Modification of personal life-style,
yoga and transcendental meditation could be profitable.
e) Health Education: The general public require preventive advice on all risk factors and related
health behaviour. The whole community must be mobilised and made aware of the possibility of
primary prevention.
f) Self-Care: An important element in community-based health programmes is patient
participation. The patient is taught self-care, i.e to take his own blood pressure and keep a log-
book of his reading. By doing so, the burden on the official health service would be considerably
reduced. Log-books can also be useful for statistical purposes.
High-Risk Strategy
This is also part of primary prevention. The aim of this approach is “to prevent the attainment of
levels of blood pressure at which the institution of treatment would be considered”. This approach
is appropriate if the risk factors occur with very low prevalence in the community. Detection of
high-risk subject should be encouraged by the optimum use of clinical methods. Since

126
hypertension tends to cluster in families, the family history of hypertension and “tracking” of blood
pressure from childhood may be used to identify individuals at risk.
2. Secondary Prevention
The goal of secondary prevention is to detect and control high blood pressure in affected
individuals. Modern anti-hypertensive drug therapy can effectively reduce high blood pressure and
consequently, the excess risk of morbidity and mortality from coronary, cerebrovascular and
kidney diseases. The control measures comprise:
(i) Early Case Detection: Early detection is a major problem. This is because high blood
pressure rarely causes symptoms until organic damage has already occurred, and the
aim should be to control it before this happens. The only effective method of diagnosis
of hypertension is to screen the population. But screening, that is not linked to follow-
up and sustained care, is a fruitless exercise. It is emphasised that screening should not
be initiated if health resources for treatment and follow-up are not adequate.

In the developed countries, mass screening is not considered essential for the adequate
control of blood pressure in the population. In Europe, the large majority of people have at least
one contact in every 2 years with the health service. If blood pressure is measured at each such
contact, the bulk of the problem of detecting those in need of intervention is solved (Hart, 1980).
(ii) Treatment: The aim of treatment should be to obtain a blood pressure below 140/90,
and ideally a blood pressure of 120/80. Control of hypertension has been shown to
reduce the incidence of stroke and other complications. This is a major reason for
identifying and treating asymptomatic hypertension. Care of hypertensive should also
involve attention to other risk factors such as smoking and elevated blood cholesterol
levels.
(iii) Patient Compliance: The treatment of high blood pressure must normally be life-long
and this presents problems of patient compliance, which is defined as “the extent to
which patient behaviour (in terms of taking medicines, following diets or executing
other life-style changes) coincides with clinical prescription”. The compliance rates can
be improved through, education directed to patients, families and the community.

4.0 Self-Assessment Exercise

1. Document the classification of high blood pressure measurement.
2. Explain the risk factors of hypertension as classified by World Health Organization Scientific
127
Group.

Answers to Self-Assessment Exercise

1. Classification of Blood Pressure Measurement
Category Systolic Blood Pressure (mm Diastolic Blood Pressure (mm
of Hg) of Hg)
Normal <130 <85
High Normal 130 – 139 85 – 90
Hypertension
Stage 1 (Mild) 140 – 159 90 – 99
Stage 2 (Moderate) 160 – 179 100 – 109
Stage 3 (Severe) >180 > 110

When systolic and diastolic blood pressure fall into different categories, the higher category should
be selected to classify the individual’s blood pressure. “Isolated systolic hypertension” is defined
as a systolic blood pressure of 140mm of Hg or more and a diastolic blood pressure of less than
90mm of Hg.

2. Risk Factors for Hypertension

Hypertension is not only one of the major risk factors for most forms of cardiovascular diseases,
but that it is a condition with its own risk factors. A World Health Organisation Scientific Group
has recently reviewed the risk factors for essential hypertension. These may be classified as:
1. Non-Modifiable Risk Factors
a) Age: Blood pressure rises with age in both sexes and the risk is greater in those with higher
initial blood pressure. Age probably represents an accumulation of environmental influence and
the effects of genetically programmed senescence in body systems. Some populations have now
been identified whose mean blood pressure does not rise with age. These communities are for the
most part primitive societies with calorie and often salt intakes at substances level.
b) Sex: Early in life there is little evidence of a difference in blood pressure between the sexes.
However, at adolescence, men display a higher average level. This difference is most evident in
young and middle aged adults. Late in life the difference narrows and the pattern may even be
reversed. Post-menopausal changes in women may be the contributory factor for this change.

128
c) Genetic Factors: There is considerable evidence that blood pressure levels are determined
in part by genetic factors, and that the inheritance is polygenic. Family studies have shown that the
children of two normotensive parents have 3 percent possibility of developing hypertension,
whereas this possibility is 45 percent in children of two hypertensive parents. Blood pressure levels
among first degree adult relatives have also been noted to be statistically significant.
d) Ethnicity: Population studies have consistently revealed higher blood pressure levels in
black communities than other ethnic groups.
2. Modifiable Risk Factors
a) Obesity: Epidemiological observations have identified obesity as a risk factor for
hypertension. The greater the weight gain, the greater the risk of high blood pressure. Data also
indicate that when people with high blood pressure lose weight, their blood pressure generally
decrease
b) Salt Intake: There is an increasingly body of evidence to the effect that a high salt intake
(i.e 7 – 8gm per day) increase blood pressure proportionately. Low sodium intake has been found
to lower the blood pressure. Besides sodium, there are other mineral elements such as potassium
which are determinants of blood pressure. Potassium antagonises the biological effects of sodium
and thereby reduces blood pressure. Potassium supplements have been found to lower blood
pressure of mild to moderate hypertensive. Calcium, cadmium and magnesium have also been
suggested as of importance reducing blood pressure levels.
c) Saturated Fat: The evidence suggest that saturated fat raises blood pressure as well as
serum cholesterol.
d) Dietary Fibre: Several studies indicate that the risk of hypertension is inversely related to
the consumption of dietary fibre. Most fibres reduce plasma and total cholesterol.
e) Alcohol: High alcohol intake is associated with an increased risk of high blood pressure.
It appears that alcohol consumption raises systolic pressure more than the diastolic. But the finding
that blood pressure returns to normal with abstinence suggests that alcohol-induced elevation may
not be fixed, and do not necessarily lead to sustained blood pressure elevation.
g) Physical Activity: Physical activity by reducing body weight may have an indirect effect
on blood pressure.

129
h) Environmental Stress: The term hypertension itself implies a disorder initiated by tension
or stress. It is an accepted fact that psychosocial factors operate through mental processes,
consciously or unconsciously leads to hypertension.
i) Socio –Economic Status: In countries that are in post transitional stage of economic and
epidemiological change, consistently higher levels of blood pressure have been noted in lower
socio-economic groups. This inverse relation has been noted with levels of education, income and
occupation, a higher prevalence of hypertension have been noted in upper socio-economic groups.
5.0 Conclusion
High blood pressure is a public health problem which affects people irrespective of their age, sex
and status. It is called silent killer, it does not usually present any signs or symptoms. It is claiming
lives of many people without knowing that they have the condition. The best way to know your
status is through regular medical check-ups. Untreated High blood pressure cases resulted to stoke,
cardiovascular problems and sometimes death.
6.0 Summary
In this unit we have discussed hypertension as a condition in which the force of the blood against
the artery walls is too high otherwise called high blood pressure. Risk factors for hypertension
were grouped into Non-Modifiable Risk Factors and Modifiable Risk Factors. World Health
Organisation recommended primary prevention and secondary prevention as approaches in the
prevention of hypertension
7.0 References/Further Reading
Hart J. T.(1980), Hypertension, Library of general practitioner series. Church hill Washington
USA
Park K. (2015). Textbook of Preventive and Social Medicine. (21st edition) Banardid Asbhanot
India. Publishers Jabalpur,
World Health Organizatio (1996). Technical Report Ser, No 862

130
Unit 3 Diabetes
CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Diabetes Mellitus
3.1.1 Classification
3.1.2 Epidemiological Determinants
3.1.3 Prevention and Control of Diabetes Mellitus
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

Remember, in the last unit you have learnt definition of hypertension, classification of blood
pressure, risk factors of hypertension and prevention and control measures of hypertension. In this

131
unit you will learn on classification of diabetes, epidemiological determinants of diabetes,
prevention and control of diabetes.

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:
 identify the classification of diabetes.
 outline the epidemiological determinants of diabetes
 describe the prevention and control measures of diabetes

3.0 Main Content

3.1 Diabetes Mellitus

Once regarded as a single disease entity, diabetes is now seen as a heterogeneous group of diseases,
characterised by a state of chronic hyperglycaemia, resulting from a diversity of aetiologies,
environmental and genetic, acting jointly. The underlying cause of diabetes is the defective
production or action of insulin, a hormone that controls glucose, fat and amino acid metabolism.
Characteristically, diabetes is a long-term disease with variable clinical manifestations and
progression. Chronic hyperglycaemia, from whatever cause, leads to a number of complications –
cardiovascular, renal, neurological, ocular, and others such as undercurrent infections (WHO,
1985)
Diabetes is an “iceberg” disease. Although increase in both the prevalence and incidence of Type
2 diabetes have occurred globally They have been especially dramatic in societies in economic
transition, in newly industrialised countries and developing countries. As at 2012 , the number of
cases of diabetes world-wide is estimated to be around 347 million, of these more than 90 percent
are type 2 diabetes. In 2008 an estimated 1.2 million people died from consequences of high blood
sugar. More than 80 percent diabetes deaths occur in low and middle income countries.
Unfavourable lifestyle and dietary habits that are associated with urbanisation are believed to be
the most important factors for the development of diabetes. The prevalence of diabetes is
approximately twice in urban areas than in rural population (WHO, 2012)
3.1.1 Classification
Park (2015), classified diabetes mellitus as follows;
1. Diabetes mellitus (DM)
i. Type 1 or insulin-dependent diabetes mellitus
ii. Type 2 or Non-insulin dependent diabetes mellitus

132
iii. Malnutrition-related diabetes mellitus (MRDM)
iv. Other types (secondary to pancreatic, hormonal, drug induced, genetic and other abnormalities).
2. Impaired Glucose Tolerance (IGT)
3. Gestational diabetes mellitus (GDM)
Type 1 Diabetes (Insulin-dependent diabetes mellitus) is the most severe form of the disease. Its
onset is typically abrupt and is usually seen in individuals less than 30 years of age. It is lethal
unless promptly diagnosed and treated. This form of diabetes is immune-mediated in over 90
percent of cases and idiopathic in less than 10 percent cases. The rate of destruction of pancreatic
β cell is quite variable. Rapid in some individuals and slow in others. Type 1 diabetes is usually
associated with ketosis in its untreated state. It occurs mostly in children, the incidence is highest
among 10-14 year old group, but occasionally occurred in adults. It is catabolic disorder in which
circulating insulin is virtually absent, plasma glucagon is elevated and the pancreatic β cells fail to
respond to all insulin genetic stimuli. Exogenous insulin is therefore required to reverse the
catabolic state, prevent ketosis, reduce the hyperglucagonaemia, and reduce blood glucose.
Type 2 diabetes is much more common than type 1 diabetes. It is often discovered by chance. It
is typically gradual in onset and occurs mainly in the middle-aged and elderly, frequently mild,
slow to ketosis and is compatible with long survival if given adequate treatment. Its clinical picture
is usually complicated by the presence of other disease processes.
Impaired glucose tolerance (IGT) describes a state intermediate – “at risk” group – between
diabetes mellitus and normally. It can only be defined by the oral glucose tolerance test.
3.1.2 Epidemiological Determinants
1. Agent
The underlying cause of diabetes is insulin deficiency which is absolute in type 1 diabetes and
partial in type 2 diabetes. This may be due to a wide variety of mechanisms (Lawrence et-al.,
2002).
(a) Pancreatic disorders – Inflammatory, neoplastic and other disorders such as cystic fibrosis.
(b) Defects in the formation of insulin -e.g. synthesis of an abnormal biologically less active
insulin molecule.
(c) Destruction of beta cells -e.g. viral infections and chemical agents.
(d) Decrease insulin sensitivity -due to increased numbers of adipocyte and monocyte insulin
receptors.

133
(e) Genetic defects -e.g. mutation of insulin gene; and
(f) Auto-immunity.
Evidence is accumulating that the insulin response to glucose is genetically controlled. The overall
effects of these mechanisms is reduced utilization of glucose which leads to hyperglycaemia
accompanied by glycosuria.
2. Host Factors
a. Age: Although diabetes may occur at any age, surveys indicate that prevalence rises steeply with
age. Type 2 diabetes usually come to light in the middle years of life and thereafter begins to rise
in frequency. Malnutrition related diabetes affects large number of young people. The prognosis
is worse in younger diabetics who tend to develop complications earlier than older diabetics.
b. Sex: In some countries e.g. UK, the overall male-female ratio is about equal. In South-East Asia,
an excess of male diabetics has been observed, but this is often to question.
c. Genetic Factors: The genetic factors of diabetes is undisputed. Twin studies shows that in
identical twins who developed type 2 diabetes, concordance was approximately 90 percent, thus
demonstrating a strong genetic component. In type 1 diabetes, the concordance was only about 50
percent indicating that type 1 diabetes is not totally a genetic entity.
d. Immune Mechanisms: There is an evidence of cell mediated and of humoral activity against
islet cell. Some people appear to have defective immunological mechanism, and under the
influence of some environmental “trigger”, attack their own insulin producing cells.
f. Obesity: Obesity particularly central adiposity has long been accepted as a risk factor for type 2
diabetes and the risk is related to both the duration and degree of obesity. Thus obesity by itself is
inadequate to account for all or even most cases of type 2 diabetes; physical inactivity and/or
deficiencies of specific nutrients may also be involved. Obesity appears to play no role in type 1
diabetes pathogenesis.
d. Maternal Diabetes: Offspring of women who are diabetic during pregnancies experience
gestational diabetes, are often large and heavy at birth, tend to develop obesity in childhood and
are at high risk of developing type 2 diabetes at an early age. Those born to mothers after they
have developed diabetes have a three-fold higher risk of developing diabetes than those born
before.
3. Environmental Risk Factors

134
Susceptibility to diabetes appeared to be unmasked by a number of environmental factors acting
on genetically susceptible individuals (Park, 2015). They include:
a. Sedentary Lifestyle: Sedentary lifestyle appears to be an important risk factor for the
development of type 2 diabetes. Lack of exercise may alter the interaction between insulin and its
receptors and subsequently lead to type 2diabetes.
b. Diet: A high saturated fat intake has been associated with a higher risk of impaired glucose
tolerance, and higher fasting glucose and insulin levels. Higher proportions of saturated fatty acids
in serum lipid or muscle phospholipids has been associated with higher fasting insulin, lower
insulin sensitivity and a higher risk of type 2 diabetes. Higher unsaturated fatty acids from
vegetable sources and polyunsaturated fatty acids has been associated with reduced risk of type 2
diabetes and lower fasting and 2-hour glucose concentrations. Higher proportions of long-chain
polyunsaturated fatty acids in skeletal muscle phospholipids have been associated with increased
insulin sensitivity. In human intervention studies, replacement of saturated by unsaturated fatty
acids leads to improved glucose tolerance and enhanced insulin sensitivity. However, long-chain
polyunsaturated fatty acids do not appear to confer additional benefit over monounsaturated fatty
acids. When total of fats intake is high (greater than 37 percent of total energy), altering the quality
of dietary fat appears to have little effect.
c. Dietary Fibre: In many controlled experimental studies, high intakes of dietary fibre have been
shown to result in reduced blood glucose and insulin levels in people with type 2 diabetes and
impaired glucose tolerance. Moreover, an increased intake of whole grain cereals, vegetables and
fruits (all rich in NSP) was a feature of diets in randomized controlled trials. Thus the evidence for
a potential protective effect of dietary fibre appears strong. A minimum daily intake of 20 grams
of dietary fibre is recommended.
d. Malnutrition: Malnutrition (PEM) in early infancy and childhood may result in partial failure
of β-cell function. Damage to beta cells may well explain the associated impaired carbohydrate
tolerance in kwashiorkor.
e. Alcohol: Excessive intake of alcohol can increase the risk of diabetes by damaging the pancreas
and liver and by promoting obesity.
f. Viral Infections: Among the viruses that have been implicated are rubella, mumps, and human
coxsackie virus B4. Viral infections may trigger in immunogenetically susceptible people a
sequence of events resulting in β-cell destruction.

135
g. Chemical Agents: A number of chemical agents are known to be toxic to beta cells, e.galloxan,
streptozotocin, the rodenticide VALCOR, etc. A high intake of cyanide producing foods (e.g
cassava and certain beans) may also have toxic effects on β-cells.
3.1.3 Prevention and Control of Diabetes Mellitus
1. Primary Prevention
Two strategies for primary prevention have been suggested:
a. Population strategy and;
b. High-risk strategy
a. Population Strategy: The scope of primary prevention of type 1 diabetes is limited on the basis
of current knowledge and is probably not appropriate. However, the development of prevention
programmes for type 2 diabetes based on elimination of environmental risk factors is possible.
There is pressing need for primordial prevention – that is, prevention of the emergence of risk
factors in countries in which they have not yet appeared. The preventive measures comprises
maintenance of normal body weight through adoption of healthy nutritional habits and physical
exercise. The nutritional habits include an adequate protein intake, a high intake of dietary fibre
and avoidance of sweet foods. Elimination of other less well defined factors such as protein
deficiency and food toxins may be considered in some populations. These measures should be
fully integrated into other community-based programmes for the prevention of non-communicable
diseases e.g coronary heart disease.
b. High-Risk Strategy: There is a special high-risk strategy for type 1 diabetes. At present, there
is no practical justification for genetic counselling as a method of prevention. Since NIDDM
appears to be linked with sedentary lifestyle, over nutrition and obesity, correction of these may
reduce the risk of diabetes and its complications. Since alcohol can indirectly increase the risk of
diabetes, it should be avoided. Subjects at risk should avoid diabetogenic drugs like oral
contraceptives. It is a wise to reduce factors that promote atherosclerosis, e.g smoking, high blood
pressure, elevated cholesterol and high triglyceride levels. These programmes may most
effectively be directed at target population groups (WHO, 2012).
2. Secondary Prevention
When diabetes is detected, it must be adequately treated. The aims of treatment are:
a. To maintain blood glucose levels as close within the normal limits as practicable and;
b. To maintain ideal body weight.

136
Treatment is based on:
a. Diet alone – small balanced meals more frequently.
b. Diet and oral anti-diabetic drugs or;
c. Diet and insulin.
Good control of blood glucose protects against the development of complications.
Proper management of the diabetics is most important to prevent complications. Routine checking
of blood sugar, of urine for protein and ketones, of blood pressure, visual acuity and weight should
be done periodically. The feet should be examined for any defective blood circulation (Doppler
ultrasound probes are advised), loss of sensation and the health of the skin. Primary health care is
of great importance to diabetic patients since most care is obtained at this level.
Self-Care: A crucial element in secondary prevention is self-care. That is, the diabetic should take
a major responsibility for his own care with medical guidance – e.g adherence to diet and drugs
regiments, examination of his own urine and where possible blood glucose monitoring; self-
administration of insulin, abstinence from alcohol, maintenance of optimum weight, attending
periodic check-ups, recognition of symptoms associated with glycosuria and hyperglycemia etc.
The patient should carry an identification card showing his name, address, telephone number (if
any), and the details of treatment he is receiving. In short, he must have a working knowledge of
diabetes. All these mean education of patients and their families to optimize the effectiveness of
primary health care services.
3. Tertiary Prevention
Diabetes is major cause of disability through its complications e.g blindness, kidney failure,
coronary thrombosis, gangrene of the lower extremities, etc. The main objective at the tertiary
level is to organise specialised clinics (Diabetic clinics) and units capable of providing diagnostic
and management skills of a high disorder. There is great need to establish such clinics in large
towns and cities. The tertiary level should also be involved in basic, clinical and epidemiological
research. It has also been recommended the local and national registries for diabetics should be
established.
4.0 Self-Assessment Exercise
1. Identify the classifications of diabetes.
2. Give detail information on primary and secondary prevention and control measures of diabetes.

Answers to Self-Assessment Exercise

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1. Classification

Park (2015), classified diabetes mellitus as follows;

1. Diabetes mellitus (DM)
i. Type 1 or insulin-dependent diabetes mellitus
ii. Type 2 or Non-insulin dependent diabetes mellitus
iii. Malnutrition-related diabetes mellitus (MRDM)
iv. Other types (secondary to pancreatic, hormonal, drug induced, genetic and other abnormalities).
2. Impaired Glucose Tolerance (IGT)
3. Gestational diabetes mellitus (GDM)
Type 1 diabetes (Insulin-dependent diabetes mellitus): This is the most severe form of the disease-
. Its onset is typically abrupt and is usually seen in individuals less than 30 years of age. It is lethal
unless promptly diagnosed and treated. This form of diabetes is immune-mediated in over 90
percent of cases and idiopathic in less than 10 percent cases. The rate of destruction of pancreatic
β cell is quite variable. Rapid in some individuals and slow in others. Type 1 diabetes is usually
associated with ketosis in its untreated state. It occurs mostly in children, the incidence id highest
among 10-14 year old group, but occasionally occurred in adults. It is catabolic disorder in which
circulating insulin is virtually absent, plasma glucagon is elevated and the pancreatic β cells fail to
respond to all insulinogenic stimuli. Exogenous insulin is therefore required to reverse the
catabolic state, prevent ketosis, reduce the hyperglucagonaemia, and reduce blood glucose.
Type 2 diabetes: This is much more common than type 1 diabetes. It is often discovered by
chance. It is typically gradual in onset and occurs mainly in the middle-aged and elderly, frequently
mild, slow to ketosis and is compatible with long survival if given adequate treatment. Its clinical
picture is usually complicated by the presence of other disease processes.
Impaired glucose tolerance (IGT) describes a state intermediate – “at risk” group – between
diabetes mellitus and normally. It can only be defined by the oral glucose tolerance test.
Q2.
1. Primary Prevention
Two strategies for primary prevention have been suggested:
a. Population strategy and;
b. High-risk strategy

138
a. Population Strategy: The scope of primary prevention of type 1 diabetes is limited on the basis
of current knowledge and is probably not appropriate. However, the development of prevention
programmes for type 2 diabetes based on elimination of environmental risk factors is possible.
There is pressing need for primordial prevention – that is, prevention of the emergence of risk
factors in countries in which they have not yet appeared. The preventive measures comprises
maintenance of normal body weight through adoption of healthy nutritional habits and physical
exercise. The nutritional habits include an adequate protein intake, a high intake of dietary fibre
and avoidance of sweet foods. Elimination of other less well defined factors such as protein
deficiency and food toxins may be considered in some populations. These measures should be
fully integrated into other community-based programmes for the prevention of non-communicable
diseases e.g coronary heart disease.
b. High-Risk Strategy: There is a special high-risk strategy for type 1 diabetes. At present, there
is no practical justification for genetic counselling as a method of prevention. Since NIDDM
appears to be linked with sedentary lifestyle, over nutrition and obesity, correction of these may
reduce the risk of diabetes and its complications. Since alcohol can indirectly increase the risk of
diabetes, it should be avoided. Subjects at risk should avoid diabetogenic drugs like oral
contraceptives. It is a wise to reduce factors that promote atherosclerosis, e.g smoking, high blood
pressure, elevated cholesterol and high triglyceride levels. These programmes may most
effectively be directed at target population groups.
2. Secondary Prevention
When diabetes is detected, it must be adequately treated. The aims of treatment are:
a. To maintain blood glucose levels as close within the normal limits as practicable and;
b. To maintain ideal body weight.
Treatment is based on:
a. Diet alone – small balanced meals more frequently.
b. Diet and oral antidiabetic drugs or;
c. Diet and insulin.
Good control of blood glucose protects against the development of complications.
Proper management of the diabetics is most important to prevent complications. Routine checking
of blood sugar, of urine for protein and ketones, of blood pressure, visual acuity and weight should
be done periodically. The feet should be examined for any defective blood circulation (Doppler

139
ultrasound probes are advised), loss of sensation and the health of the skin. Primary health care is
of great importance to diabetic patients since most care is obtained at this level.
Self-Care: A crucial element in secondary prevention is self-care. That is, the diabetic should take
a major responsibility for his own care with medical guidance – e.g adherence to diet and drugs
regiments, examination of his own urine and where possible blood glucose monitoring; self-
administration of insulin, abstinence from alcohol, maintenance of optimum weight, attending
periodic check-ups, recognition of symptoms associated with glycosuria and hyperglycaemia etc.
The patient should carry an identification card showing his name, address, telephone number (if
any), and the details of treatment he is receiving. In short, he must have a working knowledge of
diabetes. All these mean education of patients and their families to optimize the effectiveness of
primary health care services.
5.0 Conclusion
Diabetes is health condition that affects many people worldwide. It may cause permanent disability
and death among the victims. This condition is as a result of inheritance of the infected genes in
some cases, poor nutrition and lack of physical activities.
6.0 Summary
Diabetes is a metabolic health condition which occur as a result of the body inability to produce
enough (type 2 diabetes) or total in ability to produce insulin (type 1) to convert blood sugar to
release energy for body use. This condition can be prevented and control through life style changes.

7.0 References/Further Reading

Park K. (2015). Textbook of Preventive and Social Medicine.( 21st edition). Banardid Asbhanot
India. Publishers Jabalpur,.
World Health Organizatio (1985). Technical Report Ser, No 729.
World Health Organizatio (2012). Diabetes Fact Sheet No 312, Sept., 2012

World Health Organizatio (2012), Prevention and Control of Non communicable Diseases
Guidelines for Primary Health Care in low Resource settings.

140
Unit 4 Sickle Cell Anaemia and Arthritis

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Sickle cell Anaemia
3.1.1 Signs and Symptoms of Sickle cell Anaemia
3.1.2 Sickle cell Crises
3.1.3 Vaso-occlisive Occlusive Cerise
3.1.4 Spenic Sequestration Crises
3.1.5 Acute Chest Syndrome
3.1.6 Aplastic Crisis
3.1.7 Haemolytic Crisis
3.1.8 Prevention of Sickle Cell Crisis
3.1.9 Complications
3.1.10 Recommendation for Prevention of Sickle Cell
3.2 Athritis
3.2.1 Signs and Symptoms

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 3.2.2 Classification
3.2.3 General Treatment/Prevention
3.2.4 Physical Therapy
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0Introduction

In the previous unit you have learnt classification of diabetes, epidemiological determinants of
diabetes, prevention and control of diabetes. In this unit you will learn the definition of sickle cell
anaemia, sickle cell crisis stages, signs, symptoms and complications of sickle cell anaemia. Also
youwill learn meaning of arthritis, classification of arthritis, signs and symptoms and prevention
and control measures.

Sickle cell disease (SCD) is an inherited blood disorder, which affects children early in life often
with repeated episodes of catastrophic illness and bone pains with varying periods of relative good
health in between. Children with SCD are susceptible to severe infections; they have negative
nutrition balance and are less able to cope with respiratory infections and diarrhoeal diseases as it
worsens their clinical state. Less than 50% of babies with SCD will live beyond their fifth birthday
if unattended.
2.0 Intended Learning Outcomes (ILOs)
By the end of this unit, you will be able to:
 define the term sickle cell.
 identify the crisis of sickle cell
 mention signs and symptoms arthritis
 outline the classification of arthritis.

3.0 Main Content

3.1 Sickle Cell Disease (SCD)

Sickle cell disease (SCD) is an inherited blood disorder characterised by chronic anaemia
characterised by periodic episodes of pain. This disorder affects over 72,000 Americans and
millions throughout the world, most of African descent. Approximately 1 in 12 African-
Americans carry the trait for SCD and 1 of every 350 African-American infants born have the
disorder and the incidence of the disorder in Africa is ten times higher (Wethers, 2000; Ohnishi,
Ohnishi & Ogunmola, 2000). Persons with sickle cell disorder in inherit defective hemoglobin
genes from both parents. Early research was funded by the National Heart, Lung and Blood
Institute (NHLBI). The United States Congress passed the National Sickle Cell Disease Control
Act in 1972 which called for the establishment of the National Sickle Cell Disease Programme.
Over the years, this programme and others like the Cooperative Study of Sickle Cell Disease
(CSSCD), established in 1979, has funded research that has elucidated much of what we know
about the disease today, (Bonds, 2005).
Recently, it has been demonstrated that sickled red bloods cells are more susceptible to oxidative
damage than normal red blood cells and current treatments for SCD focus on applying free radical

142
chemistry to sickled cells, (Aslan, Thornley-Brown & Freeman, 2000). This information leads to
the hypothesis that the symptoms of SCD are caused by extensive free radical damage and
oxidative stress. This paper will discuss new methods for elucidating the role of free radicals in
sickle cell disease.

Three-quarters of sickle cell cases occur in Africa. World Health Organization report estimated
that around 2% of new-borns in Nigeria were affected by sickle cell anaemia, giving a total of
150,000 affected children born every year in Nigeria alone. The carrier frequency ranges between
10% and 40% across equatorial Africa, decreasing to 1–2% on the North African coast and <1%
in South Africa, (WHO, 2011). There have been studies in Africa that show a significant decrease
in infant mortality rate, ages 2–16 months, because of the sickle cell trait. This happened in
predominant areas of malarial cases, (Aidoo, Terlouw, Kolczak, McElroy, Kuile, Kariuki, Nahlen,
Lal &Udhayakumar, 2002).

3.1.1 Signs and Symptoms of Sickle Cell Disease (SCD)

Signs of sickle cell disease usually begin in early childhood. The severity of symptoms can vary
from person to person, (National Library of Medicine, 2011). Sickle cell disease may lead to
various acute and chronic complications, several of which have a high mortality rate.

3.3.2 Sickle Cell Crisis

The terms "sickle cell crisis" or "sickling crisis" may be used to describe several independent acute
conditions occurring in patients with SCD. SCD results in anaemia and crises that could be of
many types including the vaso-occlusive crisis, aplastic crisis, sequestration crisis, haemolytic
crisis, and others. Most episodes of sickle cell crises last between five and seven days. "Although
infection, dehydration, and acidosis (all of which favor sickling) can act as triggers, in most
instances, no predisposing cause is identified."

3.1.3 Vaso-Occlusive Crisis

Vaso-occlusive crisis is caused by sickle-shaped red blood cells that obstruct capillaries and restrict
blood flow to an organ resulting in ischemia, pain, necrosis, and often organ damage. Painful crises
are treated with hydration, analgesics, and blood transfusion and massage. For milder crises, a
subgroup of patients manage on nonsteroidal anti-inflammatory drugs (NSAIDs) such as
diclofenac or naproxen. For more severe crises, most patients require inpatient management.
(Olujohungbe& Burnett, 2013). Incentive spirometer, a technique to encourage deep breathing to
minimize the development of atelectasis, is recommended, (Glassberg, 2011).

3.2.4 Splenic Sequestration Crisis

Because of its narrow vessels and function in clearing defective red blood cells, the spleen is
frequently affected, (Anie & Green, 2015). It is usually infarcted before the end of childhood in
individuals suffering from sickle cell anaemia. This spleen damage increases the risk of infection
from encapsulated organisms, (Pearson, 1977).

3.1.5 Acute Chest Syndrome

Acute chest syndrome (ACS) is related with two of the following signs or symptoms: chest pain,
fever, pulmonary infiltrate or focal abnormality, respiratory symptoms, or hypoxemia.It is the

143
second-most common complication and it accounts for about 25% of deaths in patients with SCD,
majority of cases present with vaso-occlusive crises then they develop ACS, (Paul, Castro,
Aggarwal &Oneal, 2011).

3.1.6 Aplastic Crisis

Aplastic crises are condition in which the patient may develop pale appearance, fast heart rate and
fatigue. This crisis is normally triggered by parvovirus B19, which directly affects production of
red blood cells by invading the red cell precursors and multiplying in and destroying them.
Parvovirus infection almost completely prevents red blood cell production for two to three days.

3.1.7 Haemolytic Crisis

Haemolytic crises refer to rapid decrease in haemoglobin level. The red blood cells break down at
a faster rate. (Balgir, 2012).
3.1.8 Prevention of Sickle Cell Crisis

There’s no sure way, but you can lower your odds:

 Avoid swimming in cold water.
 Dress in warm clothes when it’s cold out or when you’re in air-conditioned buildings.
 Drink plenty of water.
 Fly only on commercial airlines. Planes that don’t control air pressure could cause you
problems.
 Limit how much alcohol you drink.
 Manage your stress.

It also helps to keep yourself as healthy as possible:

 Avoid being around people who are sick.

 Don’t smoke.
 Exercise, but drink plenty of liquids and don’t push too hard. Activities like intense weight
training may put too much stress on your body.
 Get prenatal care right away if you’re pregnant or you’re planning on it.
 Manage any other health conditions you may have, like diabetes, with your doctor’s help.
 Stay up to date on your shots and vaccines.
 Tell your doctor if you have any sleep problems, like snoring.
 Wash your hands often (Ratini, M. & Ms. D.,2019)

3.1.9 Complications

The complications of sickle cell anemia are: Increased risk of severe bacterial infections, Stroke,
Cholelithiasis (gallstones) and cholecystitis, Avascular necrosis (aseptic bone necrosis), Decreased
immune reactions, Priapism and infarction of the penis, Osteomyelitis (bacterial bone infection),
Acute papillary necrosis in the kidneys, Leg ulcers, In eyes, background retinopathy, proliferative
retinopathy, vitreous haemorrhages, and retinal detachments, During pregnancy, intrauterine
growth retardation, abortion, and pre-eclampsia, Chronic pain, Pulmonary hypertension and
144
Chronic kidney failure, (Caughey, Poole, Ataga&Hinderliter, 2015;. Caughey et al, 2015;
Kavanagh, Sprinz, Vinci, Bauchner& Wang, 2011; Adams, Ohene-Frempong& Wang,
2001;Almeida & Roberts, 2005).

3.1.10 Recommendation for Prevention of Sickle Cell

If you carry the sickle cell trait, seeing a genetic counselor before trying to conceive can help you
understand your risk of having a child with sickle cell anemia .Before marriage it is good to do
genotype test to confirm the status of the couples. Seek for genetic counseling for marriage to
avoid bearing children with sickle cells, if the intended parents have the potentialities of the sickle
cell condition.

3.2 Arthritis

The word arthritis is used to describe pain, swelling and stiffness in a joint or joints. Arthritis is

not a single condition and there are several different types. In another word arthritis is a term

often used to mean any disorder that affects joints (March, Smith, Hoy, Cross, Sanchez-Riera,

Blyth, Buchbinder, Vos & Woolf, 2014). Symptoms generally include joint pain and stiffness

and in some types of arthritis, other organs are also affected and onset can be gradual or sudden

(Richette & Bardin, 2010). There are over 100 types of arthritis and the most common forms are

osteoarthritis (degenerative joint disease) and rheumatoid arthritis (March et’al, 2014).

3.2.1 Signs and Symptoms

The sign and symptoms of arthritis include; pain which can vary in severity is a common symptom
in virtually all types of arthritis. Other symptoms include swelling, joint stiffness and aching
around the joint(s). Arthritic disorders like lupus and rheumatoid arthritis can affect other organs
in the body, leading to a variety of symptoms (Athanasiou, Darling, Hu, DuRaine, Reddi & Hari,
2013; Wollenhaupt & Zeidler,1998)).

Pirotta (2010) identify the following symptoms of arthritis:

 Inability to use the hand or walk

 Stiffness, which may be worse in the morning, or after use
 Malaise and fatigue

145
  Weight loss
 Poor sleep
 Muscle aches and pains
 Tenderness
 Difficulty moving the joint

3.2.2 Classification
There are several diseases where joint pain is primary, and is considered the main feature.
Generally when a person has "arthritis" it means that they have one of these diseases, which
include:
Osteoarthritis
Osteoarthritis is the most common form of arthritis and it can affect both the larger and the smaller
joints of the body, including the hands, wrists, feet, back, hip, and knee (VanItallie, 2010). The
disease is essentially one acquired from daily wear and tear of the joint; however, osteoarthritis
can also occur as a result of injury and some joint or limb deformities, such as knock-knee or
acetabular over coverage or dysplasia, have also been considered as a predisposing factor for knee
or hip osteoarthritis (Kock, Jung, & Syn, 2016). Osteoarthritis typically affects the weight-bearing
joints, such as the back, knee and hip. Unlike rheumatoid arthritis, osteoarthritis is most commonly
a disease of the elderly. More than 30 percent of women have some degree of osteoarthritis by
age 65. Other risk factors for osteoarthritis include prior joint trauma, obesity, and a sedentary
lifestyle (Jonathan, 2004).

Rheumatoid arthritis

Rheumatoid arthritis (RA) is a disorder in which the body's own immune system starts to attack
body tissues. The attack is not only directed at the joint but many other parts of the body. In
rheumatoid arthritis, most damage occurs to the joint lining and cartilage which eventually results
in erosion of two opposing bones. RA often affects joints in the fingers, wrists, knees and elbows,
is symmetrical (appears on both sides of the body), and can lead to severe deformity in a few years
if not treated. RA occurs mostly in people aged 20 and above. In children, the disorder can present
with a skin rash, fever, pain, disability, and limitations in daily activities.

146
Fig. 3.6: Picture of Rheumatoid Arthritis vs. Osteoarthritis
Lupus
Lupus is a common collagen vascular disorder that can be present with severe arthritis. Other
features of lupus include a skin rash, extreme photosensitivity, hair loss, kidney problems, lung
fibrosis and constant joint pain (WHO, 2007).

Gout
Gout is caused by deposition of uric acid crystals in the joint, causing inflammation. There is also
an uncommon form of gouty arthritis caused by the formation of rhomboid crystals of calcium
pyrophosphate known as pseudogout. In the early stages, the gouty arthritis usually occurs in one
joint, but with time, it can occur in many joints and be quite crippling. The joints in gout can often
become swollen and lose function. Gouty arthritis can become particularly painful and potentially
debilitating when gout cannot successfully be treated (Finkelstein, 2008).

Septic arthritis

Septic arthritis, also known as joint infection or infectious arthritis, is the invasion of a joint by an
infectious agent resulting in joint inflammation and symptoms typically include redness, heat and
pain in a single joint associated with a decreased ability to move the joint. Onset is usually rapid

147
and other symptoms may include fever, weakness and headache. And occasionally, more than one
joint may be involved (Chapman, 2011).

3.2.3 General Treatment/Prevention

There is no known cure for either rheumatoid or osteoarthritis. Treatment and prevention options
vary depending as earlier discussed on the type of arthritis and include physical therapy, lifestyle
changes (including exercise and weight control)..

3.2.4 Physical Therapy

Physical exercise of the affected joint can noticeably improve long-term pain relief. Furthermore,
exercise of the arthritic joint is encouraged to maintain the health of the particular joint and the
overall body of the person (Ettinger, Burns, Messier, Applegate, Rejeski, Morgan et’al, 1997;
Reid, Shengelia & Parker, 2012).
4.0 Self-Assessment Exercise
1. What are the complication of sickle cell?
2. Describe the crisis of sickle cell anaemia

Answer to Self-Assessment Exercise

Complications

The complications of sickle cell anemia are: Increased risk of severe bacterial infections, Stroke,
Cholelithiasis (gallstones) and cholecystitis, Avascular necrosis (aseptic bone necrosis), Decreased
immune reactions, Priapism and infarction of the penis, Osteomyelitis (bacterial bone infection),
Acute papillary necrosis in the kidneys, Leg ulcers, In eyes, background retinopathy, proliferative
retinopathy, vitreous haemorrhages, and retinal detachments, During pregnancy, intrauterine
growth retardation, abortion, and pre-eclampsia, Chronic pain, Pulmonary hypertension and
Chronic kidney failure, (Caughey, Poole, Ataga&Hinderliter, 2015;. Caughey et al, 2015;
Kavanagh, Sprinz, Vinci, Bauchner& Wang, 2011; Adams, Ohene-Frempong& Wang,
2001;Almeida & Roberts, 2005).

Sickle Cell Crisis

Vaso-occlusive crisis
Vaso-Occlusive Crisis is caused by sickle-shaped red blood cells that obstruct capillaries and
restrict blood flow to an organ resulting in ischemia, pain, necrosis, and often organ damage.
Painful crises are treated with hydration, analgesics, and blood transfusion and massage. For

148
milder crises, a subgroup of patients manage on nonsteroidal anti-inflammatory drugs (NSAIDs)
such as diclofenac or naproxen. For more severe crises, most patients require inpatient
management. (Olujohungbe & Burnett, 2013). Incentive spirometer, a technique to encourage deep
breathing to minimize the development of atelectasis, is recommended, (Glassberg, 2011).

Splenic sequestration crisis

Because of its narrow vessels and function in clearing defective red blood cells, the spleen is
frequently affected, (Anie& Green, 2015). It is usually infarcted before the end of childhood in
individuals suffering from sickle cell anaemia. This spleen damage increases the risk of infection
from encapsulated organisms, (Pearson, 1977).
Acute chest syndrome
Acute chest syndrome (ACS) is related with two of the following signs or symptoms: chest pain,
fever, pulmonary infiltrate or focal abnormality, respiratory symptoms, or hypoxemia.It is the
second-most common complication and it accounts for about 25% of deaths in patients with SCD,
majority of cases present with vaso-occlusive crises then they develop ACS, (Paul, Castro,
Aggarwal &Oneal, 2011).

Aplastic crisis
Aplastic crises are condition in which the patient may develop pale appearance, fast heart rate and
fatigue. This crisis is normally triggered by parvovirus B19, which directly affects production of
red blood cells by invading the red cell precursors and multiplying in and destroying them.
Parvovirus infection almost completely prevents red blood cell production for two to three days.

Haemolytic crisis

Haemolytic crises refer to rapid decrease in haemoglobin level. The red blood cells break down at
a faster rate (Balgir, 2012).
5.0 Conclusion
Sickle cell disease (SCD) is an inherited blood disorder, which affects children early in life often
with repeated episodes of catastrophic illness and bone pains with varying periods of relative good
health in between. Sickle cell disease is public health problem that affect many individuals
worldwide.
Arthritis is characterised by joint pain and stiffness and in some types of arthritis, other organs are
also affected and onset can be gradual or sudden. It has many classifications with different forms
of manifestation.
6.0 Summary
Sickle cell is an inherited health condition in which parents who are positive handed down to their
offspring. The condition is characterised with crisis and pain. It is childhood disease; the means of
preventing the condition is genetic counselling before marriage.
Arthritis occurs as result of wears and tears of life. Therefore, it cannot totally be prevented but

149
the manifestation could be early or delayed. However it is not every person that will experience
the condition. Exercise plays a significant role in managing the condition.
7.0 References/Further Reading

Aslan M, Thornley-Brown D, Freeman BA. (2000). Reactive Species in Sickle Cell Disease.
Annals of the New York Academy of Sciences. 899: 375-391.

Aidoo M, Terlouw DJ, Kolczak MS, McElroy PD, terKuile FO, Kariuki S, Nahlen BL, Lal AA,
Udhayakumar V (2002). "Protective effects of the sickle cell gene against malaria morbidity
and mortality". Lancet. 359 (9314): 1311–2. doi:10.1016/S0140-6736(02)08273-9.
PMID 11965279.

Anie KA, Green J (2015). "Psychological therapies for sickle cell disease and pain". The Cochrane
Database of Systematic Reviews (5): CD001916. doi:10.1002/14651858.CD001916.pub3.
PMID 25966336.

Adams RJ, Ohene-Frempong K, Wang W (2001). "Sickle cell and the brain". Hematology.
American Society of Hematology. Education Program. 2001 (1): 31–46.
doi:10.1182/asheducation-2001.1.31. PMID 11722977.

Almeida A, Roberts I (May 2005). "Bone involvement in sickle cell disease". British Journal of
Haematology. 129 (4): 482–90. doi:10.1111/j.1365-2141.2005.05476.x. PMID 15877730.
Archived from the original on 2012-12-16.

Bonds DR. (2005). Three decades of innovation in the management of sickle cell disease: the road
to understanding the sickle cell disease clinical phenotype. Blood Rev. 19: 99–110.

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Unit 5 Prevention and Control of Non-Communicable Diseases

CONTENTS
1.0 Introduction
2.0 Intended Learning Outcomes (ILOs)
3.0 Main Content
3.1 Prevention and Control of Non-Communicable Diseases
3.2 The World Health Organization’s Global Action Plan
3.2.1 Tobacco Use
3.2.2 Harmful Alcohol Use
3.2.3 Unhealthy Diet and Physical Inactivity
3.2.4 Health System
3.2.5 Cardiovascular Disease and Diabetes
3.2.6 Diabetes
3.2.7 Cancer
3.2.8 Research and Surveillance
4.0 Self-Assessment Exercises
5.0 Conclusion
6.0 Summary
7.0 References/Further Reading

1.0 Introduction

In the last unit you have learnt definition of sickle cell anaemia, sickle cell crisis stages, signs,
symptoms and complications of sickle cell anaemia. Also you learnt meaning of arthritis,
classification of arthritis, signs and symptoms and prevention and control measures. In this unit

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you will learn meaning of non-communicable diseases and WHO action plan on non-
communicable diseases

2.0 Intended Learning Outcomes (ILOs)

By the end of this unit, you will be able to:

 define the term non-communicable diseases
 describe the prevention and control of non-communicable diseases

3.0 Main Content

3.1 Prevention and Control of Non-Communicable Diseases
Non-communicable diseases (NCDs) are responsible the world’s largest killers, with an estimated
38 million deaths annually. Of these deaths, 16 million are premature (under 70 years of age). This
problem resulted due to attitudinal problems of people as most of these diseases are life style
related which include Cardiovascular diseases, cancer, respiratory diseases, and diabetes are the
four leading causes of NCD deaths (Pan American Health Organization, 2016).
According to World Health Organisation (2014), the four leading NCDs (cardiovascular diseases,
cancer, respiratory diseases, and diabetes) share four risk factors: tobacco use, harmful use of
alcohol, unhealthy diet, and physical inactivity. These in turn lead to other key
metabolic/physiological changes such as raised blood pressure, overweight/obesity, raised blood
glucose, and higher cholesterol levels.
3.2 The World Health Organisation’s Global Action Plan
The UN meeting in 2011 identified a target of 25 per cent reduction in mortality due to NCDs,
between the ages of 30 and 70 years, to be achieved globally by 2030. The World Health Assembly,
in May 2013, approved a global action plan for prevention and control of NCDs, along with a set
of voluntary targets and indicators linked to actions which will enable this goal to be achieved
(WHO 2013).

This plan lists nine voluntary targets which are connected to 25 indicators (Table 11.2.1). To
achieve these targets, WHO recommends the following actions.

Table 3.1 shows the Voluntary Global Targets from the Action Plan for the Prevention and Control
of Non-communicable Diseases 2013–2020

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Table 3.1 Mortality and Morbidity
1. Premature mortality from non- A 25% relative reduction in risk of premature mortality
communicable disease from cardiovascular diseases, cancer, diabetes, or
chronic respiratory diseases
2.Behavioural risk factors
Harmful use of alcohol At least 10% relative reduction in the harmful use of
alcohol, as appropriate, within the national context
3. Physical inactivity A 10% relative reduction in prevalence of insufficient
physical inactivity
4. Salt/sodium intake A 30% relative reduction in mean population intake of
salt/sodium
5. Tobacco use A 30% relative reduction in prevalence of current
tobacco use in people aged 15+ years
Biological risk factors
6. Raised blood pressure A 25% relative reduction in the prevalence of raised
blood pressure or contain the prevalence of raised blood
pressure, according to national circumstances
7. Diabetes and obesity Halt the rise in diabetes and obesity
National system response
8. Drug therapy to prevent heart attacks At least 50% of eligible people receive drug therapy and
and strokes counselling (including glycaemic control) to prevent
heart attacks and strokes
9. Essential non-communicable disease An 80% availability of the affordable basic technologies
medicines and basic technologies to and essential medicines, including generics, required to
treat major non-communicable treat major non-communicable diseases in both public
diseases and private facilities

(World Health Organization, 2013)

3.2.1 Tobacco Use

 Implement the Framework Convention on Tobacco Control (FCTC).

 Reduce affordability of tobacco products by increasing tobacco excise taxes.
 Create, by law, completely smoke-free environments in all indoor workplaces, public
places, and public transport.
 Warn people of the dangers of tobacco and tobacco smoke through effective health
warnings and mass media campaigns.
 Ban all forms of tobacco advertising, promotion, and sponsorship.

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3.2.2 Harmful Alcohol Use

 Excise tax increases on alcoholic beverages.

 Comprehensive restrictions and bans on alcohol advertising and promotion.
 Restrictions on the availability of retailed alcohol.
 Implement the WHO global strategy to reduce harmful use of alcohol.

3.2.3 Unhealthy Diet and Physical Inactivity

 Salt reduction through mass media campaigns/reduced salt content in processed foods.
 Replacement of trans-fats with polyunsaturated fats.
 Public awareness programme about diet and physical activity.

3.2.4 Health System

 Integrate highly cost-effective NCD interventions into the basic primary healthcare
package to advance the universal health coverage (UHC) agenda.
 Explore viable health financing mechanisms and innovative financing approaches, like
tobacco and alcohol taxation, to generate resources to expand health coverage.
 Improve availability of affordable basic technologies and essential medicines, including
generics, required to treat major NCDs in both public and private facilities.
 Scale-up early detection and coverage starting with very cost-effective, high-impact
interventions.
 Strengthen and reorient health systems to address NCDs and risk factors through people-
centred primary healthcare and UHC.

3.2.5 Cardiovascular Disease and Diabetes

 Educating community on the food choice with low glycaemic index for diabetic patients
and avoidance salt, fatty foods for individuals who have had heart attack or stroke and to
people with high risk of metabolic and cardiovascular diseases.
 Engaging in regular physical activities to prevent and control of diabetes and coronary
heart diseases.

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  Cardiac rehabilitation post myocardial infarction.
 Secondary prevention of rheumatic fever and rheumatic heart disease.
 Education on Care of acute stroke and rehabilitation..
 Interventions for foot care; educational programmes, access to appropriate footwear;.

3.2.6 Diabetes

 Lifestyle changes for preventing type 2 diabetes.

 Education on Influenza vaccination.
 Preconception care among women of reproductive age through patient education.
 The early detection of diabetes through careful observation of signs and symptoms to
avoid complications.

3.2.7 Cancer

 Prevention of liver cancer through hepatitis B immunization.

 Prevention of cervical cancer through periodic medical check-ups.
 Vaccination against human papillomavirus, as appropriate if cost-effective and affordable,
according to national programmes and policies.
 Population-based cervical cancer screening on regular basis.
 Population-based breast cancer mammography screening.
 Population-based colorectal cancer screening at ages over 50 years.
 Oral cancer screening in high-risk groups (e.g. tobacco users).
 Palliative care; using cost-effective treatment modalities.

Chronic respiratory disease

 Access to improved stoves and cleaner fuels to reduce indoor air pollution.
 Cost-effective interventions to prevent occupational lung diseases, that is, exposure to
silica, asbestos.
 Treatment of asthma based on WHO guidelines.
 Influenza vaccination for patients with chronic obstructive pulmonary disease.

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3.2.8 Research and surveillance

 Develop and implement a prioritized national research agenda for NCDs.

 Strengthen research capacity through cooperation with research institutes.
 Implement other policy options to promote and support national capacity for high-quality
research and development.
 Develop national targets and indicators based on global monitoring framework.
 Establish/strengthen a comprehensive NCD surveillance system, including reliable
registration of deaths by cause, cancer registration, periodic data collection on risk factors,
and monitoring national response.
 Integrate NCD surveillance/monitoring into national health information systems.
 Monitor trends and determinants of NCDs and evaluate progress in their prevention and
control.

These recommendations for national and global actions are based on evidence of high impact on
population-attributable risk and cost-effectiveness of the interventions (Beaglehole, 2011; WHO
2011d; Bonita et al. 2013). They combine policy and community level interventions which impact
on behaviours across the population and health service interventions which enable risk reduction
in individuals at high risk of NCD-related death or disability. While many of these are steered by
the health system, they will require multi-sectoral actions to influence the determinants of NCDs.
Together, they provide a comprehensive framework for prevention and control of NCDs.

For more information follow this link https://www.who.int/ncds/prevention/introduction/en/2019

4.0 Self-Assessment Exercise

1. Identify the preventive measures of cardiovascular diseases

2. Outline the preventive measures of cancer.

Answers to Self-Assessment Exercise

Q1. Cardiovascular disease and diabetes

 Educating community on the food choice with low glycaemic index for diabetic patients
and avoidance salt, fatty foods for individuals who have had heart attack or stroke and to
people with high risk of metabolic and cardiovascular diseases.
 Engaging in regular physical activities to prevent and control of diabetes and coronary
heart diseases.

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  Cardiac rehabilitation post myocardial infarction.
 Secondary prevention of rheumatic fever and rheumatic heart disease.
 Education on Care of acute stroke and rehabilitation..
 Interventions for foot care; educational programmes, access to appropriate footwear;.

Q2. Cancer

 Prevention of liver cancer through hepatitis B immunization.

 Prevention of cervical cancer through periodic medical check-ups.
 Vaccination against human papillomavirus, as appropriate if cost-effective and affordable,
according to national programmes and policies.
 Population-based cervical cancer screening on regular basis.
 Population-based breast cancer mammography screening.
 Population-based colorectal cancer screening at ages over 50 years.
 Oral cancer screening in high-risk groups (e.g. tobacco users).
 Palliative care; using cost-effective treatment modalities.

5.0 Conclusion
Non-communicable diseases (NCDs) are world’s largest killers that affect all categories of people
with an estimated 38 million deaths annually. Some non-communicable diseases (NCDs) are
cardiovascular diseases, cancer, respiratory diseases and diabetes.
6.0 Summary
Non-communicable diseases are those diseases that cannot be transmitted from one person to
another. It can be inherited or acquired later in life. They progress slowly if there is delay in taking
prevention and control measures. The one good thing about non-communicable diseases is that
they are largely preventable.

7.0 References/Further Reading

Joffres, Campbell, Manns&Tu, (2007).The burden of death, diseases, and disabilities related to
NCDs affects all but is heavily concentrated in low- and middle-income countries. NCDs act
as key barriers to development and poverty alleviation and as such are part of the sustainable
development agenda

Pan American Health Organization (2016). Communicable Diseases and Health Analysis/Health
Information and Analysis. Health situation in the Americas: core indicators 2016.
Washington, D.C.: PAHO; 2016. Available from:
http://iris.paho.org/xmlui/handle/123456789/31289?locale-attribute=en.

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World Health Organization (2014). Global status report on non-communicable diseases. Geneva:
WHO; 2014. Available from:
http://apps.who.int/iris/bitstream/10665/148114/1/9789241564854_eng.pdf?ua=1.

World Health Organization (2014). Noncommunicable diseases global monitoring framework:

indicator definitions and specifications. Geneva: WHO; 2014. Available from:
http://www.who.int/nmh/ncd-
tools/indicators/GMF_Indicator_Definitions_Version_NOV2014.pdf

Joffres MR, Campbell NR, Manns B, Tu K.(2007). Estimate of the benefits of a population-based
reduction in dietary sodium additives on hypertension and its related health care costs in
Canada. Canadian Journal of Cardiology 2007; 23(6):437–443

World Health Organization (2013). Sixty Sixth World Health Assembly; Follow-up to the Political
Declaration of the High-level Meeting of the General Assembly on the Prevention and
Control of Non-communicable Diseases. Geneva: WHO. Available at:
http://apps.who.int/gb/ebwha/pdf_files/WHA66/A66_R10-en.pdf

Beaglehole, R., Bonita, R., Horton, R., (2011). Priority actions for the non-communicable disease
crisis. The Lancet, 377(9775), 1438–47.Find this resource:

Bloom, D.E., Cafiero, E.T., Jané-Llopis, E., (2011). The Global Economic Burden of Non-
Communicable Diseases. Geneva: World Economic Forum. Available at:
http://www.weforum.org/reports/global-economic-burden-non-communicable-diseases.

Bonita, R., Magnusson, R., Bovet, P., et al. (2013). Country actions to meet UN commitments

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