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DISEASE.

DEFINITION.

Disease refers to the state of been abnormal by a body (plant and animals) that cause irregular or
unwanted physical, social or biological feeling of a body.

According to the British medical journal “A disease is a particular abnormal condition that adversely
affects the structure or function of all or part of an organism and is not immediately due to any external
injury. Diseases are often known to be medical conditions that are associated with specific signs and
symptoms”. (Robin S. Robert, 1979)

A disease is the sum of the abnormal phenomena displayed by a group of living organisms in
association with a specified common characteristic or set of characteristics by which they differ from
the norm for their species in such a way as to place them at a biological disadvantage.

Types of disease

There are four main types of disease: infectious diseases, deficiency diseases, hereditary diseases
(including both genetic and non-genetic hereditary diseases), and physiological diseases. Diseases can also
be classified in other ways, such as communicable versus non-communicable diseases, it is also be classified
as infectious disease, genetic disease, metabolic disease and External disease. Diseases can be categorized
into many types. There are primary and secondary diseases that develop from them, short-term acute and
long-term chronic illnesses, infectious and non-infectious diseases, and local and systemic diseases.

INFECTIOUS DISEASE

Infectious diseases are illnesses caused by harmful organisms (pathogens) that get into your body from
the outside. Pathogens that cause infectious diseases are viruses, bacteria, fungi, parasites and, rarely,
prions. You can get infectious diseases from other people, bug bites and contaminated food, water or soil.
 Type of infectious Disease

Infectious diseases can be viral, bacterial, parasitic or fungal infections. There’s also a rare group
of infectious diseases known as transmissible spongiform encephalopathies (TSEs).

Viral infections. Viruses are a piece of information (DNA or RNA) inside of a protective shell (capsid).
Viruses are much smaller than your cells and have no way to reproduce on their own. They get inside your
cells and use your cells’ machinery to make copies of themselves.

Bacterial infections. Bacteria are single-celled organisms with their instructions written on a small piece
of DNA. Bacteria are all around us, including inside of our body and on our skin. Many bacteria are harmless
or even helpful, but certain bacteria release toxins that can make you sick.

Fungal infections. Like bacteria, there are many different fungi. They live on and in your body. When your
fungi get overgrown or when harmful fungi get into your body through your mouth, your nose or a cut in
your skin, you can get sick.

Parasitic infections. Parasites use the bodies of other organisms to live and reproduce. Parasites include
worms (helminths) and some single-celled organisms (protozoa).

Transmissible spongiform encephalopathies (TSEs/prion diseases). TSEs are caused by prions — faulty
proteins that cause other proteins in your body, usually in your brain, to become faulty as well. Your body
is unable to use these proteins or get rid of them, so they build up and make you sick. Prions are an
extremely rare cause of infectious diseases.

Common infectious diseases caused by viruses:

Common cold. - The flu (influenza). - COVID-19. - Stomach flu (gastroenteritis). - Hepatitis. -
Respiratory syncytial viru s (RSV).

Common infectious diseases caused by bacteria:

Strep throat. - Salmonella. - Tuberculosis. - Whooping cough (pertussis).

Chlamydia. - gonorrhea and other sexually transmitted infections (STIs). - Urinary tract infections
(UTIs). - E. coli. - Chloridoids difficile (C. diff).

Common infectious diseases caused by fungi:

Ringworm (like athlete’s foot). - Fungal nail infections. - Vaginal candidiasis (vaginal yeast
infection). - Thrush.

Common infectious diseases caused by parasites:

Giardiasis. - Toxoplasmosis. - Hookworms. Pinworms.

 Symptoms and causes

What are the symptoms of infectious diseases?

Symptoms of infectious diseases depend on the type of illness. Fungal infections usually cause
localized symptoms, like rash and itching. Viral and bacterial infections can have symptoms in many areas
of your body, like:

Fever. Chills. Congestion. Cough. Fatigue. Muscle aches and headache.

Gastrointestinal symptoms (diarrhea, nausea, vomiting).

It’s important to see a doctor if you have any chronic (ongoing) symptoms or symptoms that get
worse over time.

MANAGEMENT AND TREATMENT

How are infectious diseases treated?

Treatment depends on what causes the infection. Sometimes your healthcare provider will
recommend monitoring your symptoms rather than taking medication.

Bacterial infections can be treated with antibiotics. The right antibiotic depends on what bacteria
causes the infection.

You can manage most viral infections with over-the-counter medications for your symptoms until
you feel better. If you have the flu, your healthcare provider may prescribe oseltamivir phosphate
(Tamiflu®) in some cases.

Fungal infections can be treated with antifungal medications. You can take them orally, like
fluconazole (Diflucan®) or put them on your skin just where the fungus is, like clotrimazole (Lotrimin®)

Parasites can be treated with antiparasitic drugs, such as mebendazole.

There are no treatments for prion diseases.

GENETIC DISEASE.
Genetic disorders occur when a mutation (a harmful change to a gene, also known as a
pathogenic variant) affects your genes or when you have the wrong amount of genetic material.
Genes are made of DNA (deoxyribonucleic acid), which contain instructions for cell functioning
and the characteristics that make you unique.
 You receive half your genes from each biological parent and may inherit a gene mutation
from one parent or both. Sometimes genes change due to issues within the DNA (mutations). This
can raise your risk of having a genetic disorder. Some cause symptoms at birth, while others
develop over time.

Genetic disorders can be:

Chromosomal: This type affects the structures that hold your genes/DNA within each cell
(chromosomes). With these conditions, people are missing or have duplicated chromosome
material.

Complex (multifactorial): These disorders stem from a combination of gene mutations and
other factors. They include chemical exposure, diet, certain medications and tobacco or alcohol
use.

Single-gene (monogenic): This group of conditions occurs from a single gene mutation.

Symptoms and Causes

What are the causes of genetic disorders?

To understand genetic disorder causes, it’s helpful to learn more about how your genes and
DNA work. Most of the DNA in your genes instructs the body to make proteins. These proteins
start complex cell interactions that help you stay healthy.

When a mutation occurs, it affects the genes’ protein-making instructions. There could be
missing proteins. Or the ones you have do not function properly. Environmental factors (also called
mutagens) that could lead to a genetic mutation include:

Chemical exposure. - Radiation exposure. - Smoking. - UV exposure from the sun.

What are the symptoms of genetic disorders?

Symptoms vary depending on the type of disorder, organs affected and how severe
it is. You may experience:

✓ Behavioral changes or disturbances.

✓ Breathing problems.
✓ Cognitive deficits, when the brain can’t process information as it should.
✓ Developmental delays that include challenges with speech or social skills.
 ✓ Eating and digestive issues, such as difficulty swallowing or an inability to process
nutrients.
✓ Limb or facial anomalies, which include missing fingers or a cleft lip and palate.
✓ Movement disorders due to muscle stiffness or weakness.
✓ Neurological issues such as seizures or stroke.
✓ Poor growth or short stature.
✓ Vision or hearing loss.
✓ Diagnosis and Tests

How are genetic disorders identified?

If you have a family history of a genetic disorder, you may wish to consider genetic
counseling to see if genetic testing is appropriate for you. Lab tests can typically show whether
you have gene mutations responsible for that condition. In many cases, carrying the mutation does
not always mean you’ll end up with it. Genetic counselors can explain your risk and if there are
steps you can take to protect your health.

If there’s a family history, DNA testing for genetic disorders can be an important part of
starting a family. Options include:

Carrier testing: This blood test shows whether you or your partner carry a mutation linked
to genetic disorders. This is recommended for everyone considering pregnancy, even if there is
no family history.

Prenatal screening: This testing usually involves blood testing from a pregnant person that
tells them how likely it is that a fetus could have a common chromosome condition.

Prenatal diagnostic testing: You can find out whether the developing fetus faces a higher
risk for certain genetic disorders. Prenatal testing uses a sample of fluid from your uterus
(amniocentesis).

Newborn screening: This test uses a sample of your newborn baby’s blood and is performed
on all babies born in Ohio. Detecting genetic disorders early in life can help your child
receive timely care if needed.

Management and Treatment.

What is treatment for genetic disorders like?

 Most genetic disorders do not have a cure. Some have treatments that may slow disease
progression or lessen their impact on your life. The type of treatment that’s right for you
depends on the type and severity of the disease. With others, we may not have treatment
but we can provide medical surveillance to try to catch complications early.

You may need:

Medications to manage symptoms or chemotherapy to slow abnormal cell growth.

Nutrition counseling or dietary supplements to help you get the nutrients your body needs.

Physical, occupational or speech therapy to maximize your abilities.

Blood transfusion to restore levels of healthy blood cells.

Surgery to repair abnormal structures or treat complications.

Specialized treatments, such as radiation therapy for cancer.

Organ transplant, which is a procedure to replace a nonfunctioning organ with one from a
healthy donor.

METABOLIC DISEASE.

Metabolic disease, any of the diseases or disorders that disrupt normal

metabolism, the process of converting food to energy on a cellular level. Thousands of
enzymes participating in numerous interdependent metabolic pathways carry out this
process. Metabolic diseases affect the ability of the cell to perform critical biochemical
reactions that involve the processing or transport of proteins (amino acids),
carbohydrates (sugars and starches), or lipids (fatty acids).

Symptoms

Most of the disorders associated with metabolic syndrome don't have

obvious signs or symptoms. One sign that is visible is a large waist circumference.
And if your blood sugar is high, you might notice the signs and symptoms of
diabetes, such as increased thirst and urination, fatigue, and blurred vision.
 Causes.
Metabolic syndrome is closely linked to overweight or obesity and inactivity. It's
also linked to a condition called insulin resistance. Normally, your digestive system breaks
down the foods you eat into sugar. Insulin is a hormone made by your pancreas that helps
sugar enter your cells to be used as fuel. In people with insulin resistance, cells don't
respond normally to insulin and glucose can't enter the cells as easily. As a result, your
blood sugar levels rise even as your body churns out more and more insulin to try to lower
your blood sugar.

Prevention.

A lifelong commitment to a healthy lifestyle may prevent the conditions that cause
metabolic syndrome. A healthy lifestyle includes:

✓ Getting at least 30 minutes of physical activity most days

✓ Eating plenty of vegetables, fruits, lean protein and whole grains
✓ Limiting saturated fat and salt in your diet
✓ Maintaining a healthy weight
✓ Not smoking.

Treatment

If aggressive lifestyle changes such as diet and exercise aren't enough, your doctor
might suggest medications to help control your blood pressure, cholesterol and blood sugar
levels.

EXTERNAL DISEASES.

The cornea is the clear tissue in the front of the eye that provides approximately
two-thirds of the focusing power of the eye. It plays an important role in focusing light onto
the retina, which gives you clear vision. When this delicate tissue is damaged, it can lead to
pain and blurry vision. Other parts of the eye surface can also be affected by disease, like
the conjunctiva (covers the front surface of the eye, except for the cornea) and sclera (the
tissue that forms the “white” of the eye).

What Are Corneal and External Diseases?

 Corneal and external diseases are eye conditions that affect the cornea and other areas
of the eye. They can lead to vision changes, pain, sensitivity to light and eye redness and irritation.
We treat all types of conditions, including:

CAUSES OF EXTERNAL DISEASES

✓ Microbes ( bacteria and virus ) and parasite

✓ Injuries (accident)
✓ Environmental factors during an individual lifetime.

Treatment of External diseases.

• Consultation of specified doctor

• Taking remedies and prescription