1. DISEASES
Smooth functioning of the human body depends upon several things
such as:
a) The food we eat
b) The air we breathe
c) The water we drink
d) Proper exercise and rest
e) Entrance of unwanted elements ( such as diseases germs) from outside
f) The state of our mind
Contaminated food, polluted air and water, improper amount of
food(unbalanced diet), bad habits(drinking, smoking, drugs, etc.) and the
entrance of the disease germs from outside through various agents(flies,
mosquitos, etc.) can make us sick and even cause death.
Apart from these there are certain stages in human life and
development. A child grows into an adult, becomes mature and soon grows
old and dies. The various organs inside the body cease to function well with
age. That is why we suffer from weak heart, kidneys, liver, teeth, bones,
etc. sometimes there is unnatural growth of tissue inside the body that
prevents smooth functioning of the organs and can even cause death.
Disease and death are natural consequences of life. However, with
proper care and precautions, we can prevent ourselves from getting diseases
too often in our lives. There are two kinds of diseases:
A) Communicable diseases
These are diseases that one person can get by contamination or contact
with a diseases person. Tetanus, typhoid, cholera, tuberculosis,
whooping cough, malaria, jaundice are the communicable diseases. Most
of the communicable diseases are caused by bacteria or virus.
B) Non-communicable diseases
Some diseases are caused not by transferable bacteria or virus, but by
some unusual changes within the body system itself. Such diseases are
generally caused by bad eating and drinking habits, lack of exercise, etc.
some none communicable diseases are inherited. Some are caused due
to old age.
Heart disease, diabetes, cancer, asthma, kidney and gall bladder stones,
high blood pressures are examples of non-communicable diseases.
How are diseases communicated?
There are several ways by which harmful germs reach the body and
cause diseases such as by the physical contact and human carriers, by
wound, by insect bite, by dust and dirt, by infect droplets in the air,
etc.

2. A) Personal contact :
Some diseases such as skin disease and syphilis are caused by actual
physical contact or by the contact with some articles used by
diseased person. These articles may be spoons and forks, glasses,
towels, bed, clothes and toilet. Such things must be cleaned
especially with Dettol or iodine water.
B) Human carriers:
There are some who can harbor diseases germs without themselves
being the victims of such disease and without knowing that they are
the victims of such diseases and without knowing that they are
causing diseases. Examples of such diseases are typhoid fever and
diphtheria.
C) Food:
Infected particles of dust may settle on food or in milk. Food may
also be infected by flies, or touched by people with dirty hands
containing germs.
D) Water:
Infection by water may be through contamination at the source, by
sewerage or by the workers who are disease carriers. Typhoid fever,
cholera and dysentery are the examples of disease caused by
infected water.
E) Wound and insect bites:
If the skin is pricks, cut or grazed, bacteria can find their way to the
blood and cause infection. Tetanus blood anthrax can be carried in
this manner. Insect bites also can cause disease if the insects have
also germs. Dust and any form of dirt commonly harbor germs and
will therefore cause infection if they enter the body through wounds.
F) Droplet infection:
Any one suffering from common cold, influenza, diphtheria,
tuberculosis and other diseases of the respiratory tract passes the
germs in the air in minute droplets of moisture which are exhaled in
breath or ever when speaking. Sneezing and coughing shoot out these
droplets with considerable force. Such droplets may directly enter
the respiratory tract of nearby persons or get dried up among the
dust and so get carried to other people. Such air-borne infection can
be very easily contacted.
G) Certain animals such as insects, rats, mice and domestic animals and
pets, may bear disease germs. For example, malaria germs are
carried by female mosquito anopheles, germs of sleeping sickness are
carried by tse-tse fly, and rabies virus are carried by dogs, and typhus

3. virus by lice. Rabies can also be carried by other animals such as
rabbits, bats, foxes, mice, wolves and even domestic animals.
In this unit, we will study about symptoms, ways of communications
and prevention of a few communicable diseases.
1. Diarrhea
Persons suffering from diarrhea discharge frequent watery stool
and often gets pain in the abdomen. Diarrhea is usually caused by
bacterial infection of the alimentary canal. Cholera is caused by
infection of cholera bacteria, which appears like a comma (,)
under the microscope.
Symptoms:
-frequent watery stool and pain in the abdomen
-indigestion and loss of appetite
-twitching of muscles
-parched throat and feeling of thirst
-onset of fever after a few days of diarrhea
Communication of diarrhea
Disease germs causing diarrhea communicate through polluted water and food. Flies
help in the process of communication. Children may be infected if proper care is not taken
to boil milk and if uncleansed feeding bottles are used.
Prevention
The stool and urine of person suffering from diarrhoea should not be thrown around but
should be covered by soil.
- Foods should be protected from flies.
- Raw and rotten vegetables should be avoided.
- Fruits should be properly washed with water.
- Water resources should not be polluted. In case water is polluted, it should be boiled
or disinfected before use.
- Latrine should be used properly.
- In case of diarrhoea plenty of fluids should be taken. A mixture of salt, sugar and
water (jeevan jal) should be used.
2. Round worm
Round worms are the parasites that remain inside the intestine and use
much of the valuable nutrients from the food. Besides, they cause pain
in the abdomen, and we lose weight. The scientific name of roundworm
is ascaris lumbricoida.
Symptoms:
- Abdominal pain and slightly loose stool
- Sleeplessness and loss of body weight
- Nausea and quick breathing
- Itching sensation in the anus
- Diarrhoea and uncommon appetite.

4. Communication
The stool of a person infected by the roundworms contain large number of ova (eggs).
These eggs get mixed soil, water and vegetables.
Children walking barefooted in dirty soil often get infected with roundworms.
Vegetables grown in soil infected by roundworms eggs, if eaten raw may cause
roundworm infestation.
On reaching the intestine the eggs develop into larvae which make their way into
the blood and this carries them to the lungs, from the lungs they get entry into the
bronchi and trachea and so by the oesophagus to the stomach. On reaching the
intestine, the larvae develops into adult worm. The full cycle takes about 14 days
for completion. Diarrhoea and an unusually large appetite are common symptoms.
Prevention
- Wash fruits and vegetables carefully before eating.
- Use safer water.
- Dispose stool and urine safely.
- Use latrine properly.
- If someone is infected with worms, everybody in the home should be treated with
medicine. Usually it is safe to medicine for roundworm infestation once a year.
3. Hookworm
It is also a parasite that remains lodged in the intestine.
Symptoms
- Anaemic condition develops since hookworms feed on the blood of the host.
- Loss of body weight.
- Indigestion and frequent belching
- Nausea and loss of appetite.
Communication
The stool of a person infected with hookworm contain several eggs. Eggs develop
into larvae in moist places. If someone walks barefooted on such soil, the hookworm
larvae enter the body through the moist skin between toes. The larvae enters the
blood stream and get lodged in the lungs, and find way to the intestine through
trachea and oesophagus. Once they reach the intestine they develop into full worm
within about 3 weeks.
Prevention
- Stool should be disposed properly and not mixed with soil.
- Using open places for passing stool should be discouraged.
- Children should not walk barefooted in soil containing hookworm eggs. Using slippers
won’t help prevent larvae from reaching the toes.
- After playing in the playground, hands and feet should be washed to remove soil
particles.
- Persons should be discouraged from passing stool in open places.
4. Scabies
Scabies causes itching sensation in the skin. It is quite common in the
children. It is caused by a minute animal parasite which burrows under

5. the skin. The ‘itch’ mite is a small spider like insect, rather rounded or
oval in shape. The body of female mite is about 0.35-0.45 mm long.
The male is smaller. It bears four pair of short legs but no wings, the
female burrows into the skin and forms small channels in which it lays
eggs.
The female dies after laying eggs. The larvae which hatch from the eggs
burrow deep into the skin causing skin irritation. Scratching causes
inflammation and formation of scales. The mites becomes matured
after about three weeks. The mature mites comes to the surface for
mating. The male dies after mating. The fertilized female now starts
burrowing through the skin to lay eggs. Thus the cycle continues.
Prevention
- The person suffering from scabies should be isolated; clothes should not be
exchanged since the female mite can remain in the clothes if she cannot find a
proper place to lay eggs.
- The person suffering from scabies should be treated. Usually a solution of a medicine
called benzyl benzoate is applied on the skin surface.
- Cleanliness should be maintained in home and the surrounding.
- Children suffering from scabies should be sent to school only after being properly
treated.
- Clothes used by a person suffering from scabies should be properly washed and dried.
It is better to steam or dip such clothes in boiling water before applying soap and
washing.
5. Conjunctivitis
This is an eye disease in which the conjunctiva of the eye becomes
swollen and red, brought about by irritation caused by the entry of the
foreign agents or microorganisms. It is extremely infectious.
The conjunctiva is a thin mucous membrane which lies between the
movable eyelids and the front of the eye ball.
Symptoms
- Red and swollen eye
- Irritating eye balls, tears and burning sensation
- Sticky fluid in the eye
Prevention
- Avoid contact with the persons suffering from this disease
- Protect eyes from dust and dirt.
- Person suffering from conjunctivitis should be treated early and not get mixed with
other persons before recovery.
6. Common cold
This disease is caused by virus. Common cold is so common that it is not
considered as a disease. Everybody gets common cold two or three
times a year, but children get infected quite often.

6. Symptoms
- Irritation of throat and nose
- Running nose, cough and change in voice
- Breathing difficulties
- Watery eyes
- Feverish feeling, headache and pain in the joints.
Communication
The cold causing the viruses come out with breathe of the diseased person while
sneezing or coughing. These viruses are usually mixed up with droplets of water,
which come out with force while sneezing or coughing. So a person happened to
intake the virus catches cold; staying in a closed room with person suffering from
cold lead to infection. Sometimes use of drinking glass, clothes and other articles of
the diseased person will help in spreading the disease.
Prevention
- Since this is a disease come by air, it is better to isolate the diseased person and
treat him in a well-ventilated room.
- The patient should close his nose and mouth with the handkerchief while sneezing.
- Articles used by the patient should not be used by other persons.
- Travelling in stuffy buses and living in crowded, ill ventilated place (like cinema-
hall) should be avoided.
- Use of vitamin C in the diet regularly helps build body resistance against the disease.
- In case of severe cold of flu it is better to consult a doctor and use medicines. Taking
plenty of fluids and rest helps quick recovery.
7. Jaundice
Jaundice or ‘yellow disease’ as it is commonly called, is caused by
disorder in the function of the liver. This may be due to virus infection
or by the obstruction of the flow of bile into the intestine. Jaundice
caused by virus is communicated from person to person.
Symptoms:
- Yellow colour of the eye balls, yellowish patch under the tongue.
- Deep yellow urine
- Foul smelling stool
- Itchy skin
Prevention
- Isolate persons suffering from jaundice and stop the use of the articles used by
diseased persons.
- Maintain cleanliness in the surrounding.
- Keep river water clean and unpolluted.
- Decrease the amount of fats and spices in the diet.
- Disinfect urine and stool of the patients and bury them.
Jaundice caused by obstruction of the bile duct (by the gall bladder stone) is not
communicable. This kind of jaundice should be referred to a doctor. Usually in such
case, the gall bladder is operated and the stones are removed.

7. 8. Rabies
This diseases is caused by a virus. This virus is transferred from bites or
licks of diseased dogs or other animal suffering from rabies. The disease
is always fatal to human beings but prevention of its development after
being bitten by a rabies dog or from other sources of infection is
successful if immunizing vaccine is given before the symptoms develop.
Unfortunately, rabies infected dogs do not always reveal the symptoms
for several months.
Symptoms
- Extremely painful spasm in the throat when trying to swallow causes fear of drinking
hence the name hydrophobia (fear of water) given to the disease.
- Light fever with vomiting tendency.
- Saliva flow from the mouth.
- Restlessness.
Prevention
- Kill stray dogs.
- Give anti-rabies vaccine to pet dogs.
- Prevent children from playing with dogs.
- Take anti-rabies vaccine if bitten by a suspected dog(if possible the dog should be
kept in watch for about 15 days within which period the dog should die if infected
by the rabies)
- Kill and bury animals suffering from rabies.