PROJECT REPORT ON HUMAN DISEASES
A disease is a condition of the body or apart of it in which functions are disturbed or
arranged. Diseases may also be defined as morphological , physiological , psychological
disturbance in the body or body parts caused by some external agencies which may be non-
parasitic e.g. deficiency of nutrients or may be parasitic caused by causes, bacteria , fungi
etc. The term disease means DIS-EASE or discomfort. In short it can be defined as ‘diseases is
disorder of body’.
SOURCES OF DISEASES
The reservoir of human diseases are:
a) Air: It is reservoir of pathogens of many diseases like, measles, mumps, tuberculosis,
diphtheria etc.
b) Food and Water: These are reservoir of pathogens of many diseases like, cholera, polio,
typhoid, roundworm, tapeworm etc.
c) Soil: It is a reservoir of pathogen of tetanus diseases.
d) Animals: These are those living organisms which spread the pathogens from an infected
person of healthy person. These do not suffer from the diseases so are also called
reservoir host.
TYPES OF DISEASES
Diseases are broadly classified into two categories:
A. CONGENITAL DISEASES
Diseases present since birth and are caused due to defective development of
inheritance e.g. congenital heart diseases, hemophilia, colour blindness etc.
B. Acquired diseases
Diseases developed after birth. They are further classified as-
a) Communicable diseases
b) Non-Communicable diseases
Pathogen
A pathogen or infectious agent is a biological agent that causes disease or
illness to its host.
The term is most often used for agents that disrupt the normal physiology of a multicellular animal or
plant.
However, pathogens can infect unicellular organisms from all of the biological kingdoms.
There are several substrates and pathways whereby pathogens can invade a host.
The human body contains many natural defenses against some of common pathogens in the form of
the human immune system and by some "helpful" bacteria present in the human body's normal flora.
Some pathogens have been found to be responsible for massive amounts of casualties and have
had numerous effects on afflicted groups.
Today, while many medical advances have been made to safeguard against infection by pathogens,
through the use of vaccination, antibiotics and fungicide, pathogens continue to threaten human life.
Social advances such as food safety, hygiene, and water treatment have reduced the threat from
some pathogens.
TYPHOID
Typhoid fever is an acute illness associated with fever
caused by the Salmonella enterica serotype
Typhi bacteria. It can also be caused
by Salmonella paratyphi, a related bacterium that
usually causes a less severe illness. The bacteria are
deposited in water or food by a human carrier and are
then spread to other people in the area.
The incidence of typhoid fever in the United States has
markedly decreased since the early 1900s, when tens of
thousands of cases were reported in the U.S. Today, less
than 400 cases are reported annually in the United
States, mostly in people who have recently traveled to
Mexico and South America. This improvement is the
result of better environmental sanitation. India,
Pakistan, and Egypt are also known as high-risk areas
for developing this disease. Worldwide, typhoid fever
affects more than 21 million people annually, with about
200,000 people dying from the disease.
WIDAL TEST
In 1896 and named after its inventor, Georges-Fernand
Widal, is a presumptive serological test for enteric
fever or undulant fever whereby bacteria causing typhoid
and protozoa causing malaria fever are mixed with a
serum containing specific antibodies obtained from an
infected individual. In cases of Salmonella infection, it is a
demonstration of the presence of O-soma false-positive
result. Test results need to be interpreted carefully to
account for any history of enteric
fever, typhoid vaccination, and the general level of
antibodies in the populations in endemic areas of the
world. Typhidot is the other test used to ascertain the
diagnosis of typhoid fever. As with all serological tests, the
rise in antibody levels needed to perform the diagnosis
takes 7–14 days, which limits its applicability in early
diagnosis. Other means of diagnosing Salmonella
typhi (and paratyphi) include cultures of blood, urine
and faeces. These organisms produce H2S from
thiosulfate and can be identified easily on differential
media such as bismuth sulfite agar.
PNEUMONIA
Pneumonia is an infection that inflames the air
sacs in one or both lungs. The air sacs may fill
with fluid or pus (purulent material), causing
cough with phlegm or pus, fever, chills, and
difficulty breathing. A variety of organisms,
including bacteria, viruses and fungi, can cause
pneumonia.
Pneumonia can range in seriousness from mild
to life-threatening. It is most serious for infants
and young children, people older than age 65,
and people with health problems or weakened
immune systems.
COMMON COLD
The common cold, also known simply as a cold,
is a viral infectious disease of the upper
respiratory tract that primarily affects
the nose.[7] The throat, sinuses, and larynx may
also be affected.[5] Signs and symptoms may
appear less than two days after exposure to the
virus.[5] These may include coughing, sore
throat, runny nose, sneezing, headache,
and fever.[2][3] People usually recover in seven to
ten days,[2] but some symptoms may last up to
three weeks.[6] Occasionally those with
other health problems may develop pneumonia.[2]
Well over 200 virus strains are implicated in
causing the common cold,
with rhinoviruses being the most
common.[11] They spread through the air during
close contact with infected people or indirectly
through contact with objects in the environment,
followed by transfer to the mouth or nose.[2] Risk
factors include going to child care facilities, not
sleeping well, and psychological stress.[5] The
symptoms are mostly due to the
body's immune response to the infection rather
than to tissue destruction by the viruses
themselves.[12] In contrast, those affected
by influenza can show similar symptoms as
people with a cold, but symptoms are usually
more severe.[5] Additionally, influenza is less
likely to result in a runny nose.[13]
MALARIA
Malaria is an infectious disease caused by
a parasite: it is spread by the bite of an
infected mosquito. People catch malaria when the
parasite enters the blood. The parasite causes a
deadly infection which kills many people each
year.
The parasite that causes malaria is
a protozoan called 'Plasmodium'. Protozoa are
organisms with only one cell, but they are
not bacteria. Bacteria are smaller and simpler than
protozoans.
People usually get malaria from
the Anopheles or Culex mosquitoes: they are
the vectors of the disease. The Plasmodium gets
into people by the bites of mosquitoes.
The Plasmodium is in the mosquito's special
saliva.[1] The mosquito's saliva injects an
anticoagulant into the person to prevent their
blood from clotting. The person is then infected
with Plasmodium as a by-product. This makes the
person have the disease we call malaria.
Only the female mosquito gives people malaria,
because only the female mosquito consumes
blood. The male mosquito lives on the nectar of
flowers. The female uses blood as a source of
protein for its eggs.
ASCARIASIS
Infection with Ascaris lubricoides, the intestinal
roundworm, the most common worm infection in
humans.
Ascaris eggs are found in the soil. Infection occurs
when a person accidently ingests (swallows) infective
ascaris eggs. Once in the stomach, larvae (immature
worms) hatch from the eggs. The larvae are carried
through the lungs then to the throat where they are then
swallowed. Once swallowed, they reach the intestines
and develop into adult worms. Adult female worms can
grow over 12 inches (4.8 cm) in length. Adult male
worms are smaller. Adult female worms lay eggs that
are then passed in feces; this cycle takes between 2
and 3 months. Adult worms can live 1 to 2 years.
Infection occurs worldwide. It is most common in
tropical and subtropical areas where sanitation and
hygiene are poor. Children are infected more often than
adults. In the US, infection is not common and occurs
mostly in rural areas of the southeast.
ELEPHANTIASIS
Elephantiasis refers to a parasitic infection that
causes extreme swelling in the arms and legs.
The disease is caused by the filarial worm, which is
transmitted form human to human via the female
mosquito when it takes a blood meal. The parasite
grows into an adult worm that lives in the lymphatic
system of humans.
Elephantiasis is typically characterized by
a thickening of the skin and subcutaneous
tissue that gives rise to the grossly
enlarged and swollen limbs that earn the
condition its name. The condition is also
called lymphatic filariasis.
RING WORM
Ringworm is a common infection of the skin and nails that is caused by fungus.
The infection is called “ringworm” because it can cause an itchy, red, circular rash.
Ringworm is also called “tinea” or “dermatophytosis.” The different types of
ringworm are usually named for the location of the infection on the body.
Areas of the body that can be affected by ringworm include:
Feet (tinea pedis, commonly called “athlete’s foot”)
Groin, inner thighs, or buttocks (tinea cruris, commonly called “jock itch”)
Scalp (tinea capitis)
Beard (tinea barbae)
Hands (tinea manuum)
Toenails or fingernails (tinea unguium, also called “onychomycosis”) Click
here for more information about fungal nail infections.
Other parts of the body such as arms or legs (tinea corporis)
Approximately 40 different species of fungi can cause ringworm; the scientific
names for the types of fungi that cause ringworm are Trichophyton, Microsporum,
and Epidermophyton.1
DENGUE AND CHIKUNGUNYA
Chikungunya is a mosquito-borne viral disease first described during an outbreak
in southern Tanzania in 1952. It is an RNA virus that belongs to the alphavirus
genus of the family Togaviridae. The name “chikungunya” derives from a word in
the Kimakonde language, meaning “to become contorted”, and describes the
stooped appearance of sufferers with joint pain (arthralgia).
Signs and symptoms
Chikungunya is characterized by an abrupt onset of fever frequently
accompanied by joint pain. Other common signs and symptoms include
muscle pain, headache, nausea, fatigue and rash. The joint pain is often
very debilitating, but usually lasts for a few days or may be prolonged to
weeks. Hence the virus can cause acute, subacute or chronic disease.
Dengue fever is a mosquito-borne tropical disease caused by the dengue
virus.[1] Symptoms typically begin three to fourteen days after infection.[2] This may
include a high fever, headache, vomiting, muscle and joint pains, and a
characteristic skin rash.[1][2] Recovery generally takes two to seven days.[1] In a small
proportion of cases, the disease develops into severe dengue, also known
as dengue hemorrhagic fever, resulting in bleeding, low levels of blood
platelets and blood plasma leakage, or into dengue shock syndrome,
where dangerously low blood pressure occurs.[1][2]
Dengue is spread by several species of female mosquitoes of the Aedes type,
principally A. aegypti.[2][1] The virus has five types;[7][8] infection with one type usually
gives lifelong immunity to that type, but only short-term immunity to the
others.[1] Subsequent infection with a different type increases the risk of severe
complications.[1] A number of tests are available to confirm the diagnosis including
detecting antibodies to the virus or its RNA.[2]
