Communicable Diseases Symptoms and Prevention
Communicable Diseases Symptoms and Prevention – CBSE Class 9 Science
In this article, we will discuss the topic ‘
Communicable Diseases Symptoms and Prevention‘, from Chapter 5 – out for Why do we fall ill Class 9 Science.
Communicable diseases are those which get transferred from one person to another or one animal to a person or another animal by means of any contamination.
Communicable Diseases are :-
Malaria is insect-borne disease and caused by a parasitic protozoan,
Plasmodium completes its life cycle in two hosts, man, and female Anopheles mosquito It is transmitted from person to person by the bite of the insect vector, the female
Anopheles When a mosquito bites an infected person, the protozoa are sucked into the stomach of insect along with the blood and breed there.
These parasites complete their life-cycle when they enter the red blood corpuscles in man and destroy them.
High fever, headache, body ache, nausea, and shivering are some of the symptoms of malaria.
Each malarial attack lasts for 6-10 hours and consists of the cold stage (shivering), hot stage (fever) and sweating stage (temperature goes down to normal).
Efforts must be made to prevent mosquitoes from biting and also prevent them from Breeding
Following are some such methods:
Use wire mesh on doors and windows to prevent entry of mosquitoes into the house
Use mosquito repellents to prevent mosquito bites
Spray kerosene on stagnant water bodies or introduce fishes that feed on mosquito larva into the water bodies, so that the larvae are killed
Example of larvae eating fishes:
Gambusia, Minnows, Trouts Spray insecticides like Malathion, BHC
Clean tanks and sumps regularly
Do not allow rainwater to collect and stagnate in the garden
Quinine – which is an extract from the cinchona tree is used to manufacture chloroquine. This drug kills the malarial parasite.
This is an airborne disease caused by a virus called
It spreads through droplet infection.
The virus attacks the mucous membrane of the nose.
Running nose, sneezing, coughing, body ache, and fever are some of the symptoms of this disease.
Avoid physical contact with patients suffering from
Being viral there is no known control for influenza.
Drugs like Rimantidine, Paracetamol (like crocin) are used.
Rest helps in speedy recovery.
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Jaundice is the disease that affects the liver which is caused by viral infection.
The types of hepatitis are A, B, C, D, E, and
Out of all these, Hepatitis B is the most
Hepatitis A infection spreads through contaminated food and water.
Hepatitis B infection spreads through infected blood, contaminated needles, from mother to babies and it is also an STD.
Symptoms of Hepatitis A
There is a loss of appetite.
Body ache, nausea, vomiting, weakness.
Eyes and skin turn yellow.
Urine is dark yellow and the stools are light yellow.
The other symptoms are a headache, temperature, and pain in the joints.
Use potable water that is chlorinated, boiled, filtered and ozonized
Prevent infection through physical contact by washing hands thoroughly after handling any article used by the patient
Hepatitis-B vaccine should be taken to prevent the disease
Interferon injection are effective to control the disease
Adequate rest is required for the patient to recover fast
Sugarcane juice, radish with jaggery are recommended
Fats should be avoided and protein taken within limits
This is a canine disease which is transmitted to man through the bite of a rabid dog or other rabid mammals such as monkeys, cats or rabbits.
This is a viral disease caused by a rabies virus, which is present in the saliva of the infected animal.
The patient develops a severe headache, high fever, painful contractions of the throat muscles and chest.
The patient feels restless, shows excessive salivation and difficulty in swallowing
Hydrophobia (fear of water) sets in as the virus selectively attacks the brain i.e., the nervous system.
Damage to the central nervous system causes paralysis and painful death.
Wash the wound with antiseptic soap, and clean water.
Apply an antiseptic and consult the doctor for anti-rabies vaccine
Pet dogs or cats should be immunized by getting them vaccinated with an anti-rabies vaccine
A rabid dog can be easily identified because it will show excessive salivation and try to seek isolation after biting.
To prevent further transmission of the disease the dog should be killed.
Rabies can be treated by Pasteur’s treatment (A course of 14 vaccines was given)
Advanced treatment- Five anti-rabies vaccines are prescribed at an interval 0-3-7-14-30 days of the bite.
AIDS stands for
“Acquired Immuno Deficiency Syndrome” (as the virus affects the immune system of the body) AIDS was first detected in June 1981 in the USA.
The disease is caused by a virus – HIV (Human Immuno Deficiency Virus).
The HIV attacks the “T” lymphocytes and uses the genetic material to produce more virus particles which are released into the blood to attack more lymphocytes (WBC).
This leads to the destruction of the white blood corpuscles and reduces the body’s defense against infections like pneumonia and also some kinds of cancer.
HIV is transmitted when there is an exchange of body fluids from an infected person to a healthy one.
The common modes of transmission are:
Sharing needles to inject drugs
From HIV positive mother to unborn child
Razor at the hairdressing saloon
The incubation period (the period between infection and the first appearance of symptoms) is 1-10 years.
The important symptoms of AIDS are: Swollen lymph nodes
Low blood platelet count, causing hemorrhage and fever, weight loss and sweating at night
Severe damage to the brain which may lead to loss of memory, ability to speak and think clearly
Due to the breakdown of the immune system, the patient becomes susceptible to other infections
The public must be educated to take the preventive measures against AIDS.
A disposable or new razor should be used by the hair dresser’s • Blood donors must be screened for HIV before they donate blood.
Only disposable needles and syringes should be used.
Contraceptives like Condom must be used and Safe sex must be practiced Control
No effective vaccine for AIDS has been developed so far.
The bacterium that causes this disease is Mycobacterium tuberculosis
It is a rod-shaped bacteria spread by air, dust, sputum of an infected person or even from animals.
The bacterium releases a toxin called tuberculin.
The disease generally affects lung tissue but may spread to any other part of the body like the brain, stomach or intestine.
TB is completely curable
The first symptoms observed are persistent coughing and weight loss.
The patient feels sick and weak.
There is a loss of appetite.
There is a low grade fever which may arise in the afternoon.
Depending on the affected organ TB can be of different types-
The affected organ is lung
The patient has a persistent cough and produces blood containing sputum.
There are weight loss and a feeling of weakness.
Pain in the chest and breathlessness may also occur.
Lymph Gland T.B.
Public awareness of health and hygiene is essential
BCG ( Bacillus-Calmette-Guerin) vaccination which contains weakened
Tuberculosis bacillus is injected into the system to produce antibodies that will fight the disease
Cows that are milked should be immunized with tuberculin vaccine
Spitting in public places must be banned
ATT (Anti-tubercular therapy) should be administered.
Streptomycin (antibiotic) is an effective drug.
Cholera is a water-borne disease which is transmitted by flies.
The infection can occur in a large area especially during the flood and other natural calamities.
The bacterium that causes the disease is Vibrio cholerae.
There is severe gastrointestinal infection (infection of the digestive system) which leads to vomiting, watery motions, reduced urination and
Eyes become sunken and the patient gets muscle cramps.
Immunization with anti-cholera The immunization lasts for 6 months
When the disease spreads precautions like boiled water, properly cooked food must be consumed.
Exposed food should be avoided.
Proper sanitation and good personal hygiene in the community will prevent the spreading of the disease
To prevent dehydration ORS (Oral Rehydration Solution) should be given to the infected person to make up for the loss of water and salts.
ORS can be prepared by mixing – Sodium chloride 3.5 g + sodium bicarbonate 2.5 g,+ Potassium chloride
1.5 g + Glucose 20.0 g + Sucrose 40 gm + Water 1 L.
Immediate medical help is required to control the disease.
Tetracycline (antibiotic) is effective in controlling cholera.
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This is the most communicable disease in our country and affects mainly children in the age group 0-15 years.
Caused by bacterium
Salmonella typhi, it passes out through the excreta of the infected person. Typhoid is spread by houseflies or directly through contaminated food especially milk and eggs.
A headache and high fever for three to four weeks.
The temperature reaches its peak in the afternoon
If care is not taken, relapse(recurrence) is common
Control of flies
Anti typhoid vaccines.
Ciproflox Is the most drug used.
Bacteria such as
coli, Shigella, some types of protozoa ( Entamoeba) and viruses cause this disease. The most common symptom of Diarrhoea is frequent loose motions accompanied with abdominal pain.
Frequent loose motion and vomiting leading to dehydration
If neglected can result in dehydration.
The patient becomes irritable, eyes look sunken, mouth gets dry.
There is sudden weight loss,
Pulse is weak accompanied with deep breathing and convulsions
Eatables should be kept covered to prevent contamination through dust and flies
Fruits and vegetables should be washed with potassium permanganate, before use
Water should be boiled before drinking. Filtered water and mineral water are also safe
Proper sanitation and toilet facilities are essential
Proper personal hygiene, like washing hands before eating or handling food is important
Food that is stale or has got rancid should not be consumed
Public should be educated about community hygiene
Total bed rest is advised for the patient till the illness is fully controlled
Sufficient fluids must be taken.
ORS should be given regularly at short intervals.
Antimicrobial drugs and anti-diarrhoeal drugs are prescribed by the doctors.
A good home remedy is to take the pulp of boiled raw banana, turmeric, salt and lime
Poliomyelitis or polio is caused by Polio virus (smallest virus).
The virus enters the body through food and water.
The virus is excreted out in the faecal matter of the infected person, the virus can enter through faeco-oral route.
The virus first reaches the intestine and finally to the Nervous system.
Polio is the disease of the nervous system, the virus destroys the motor nerves which are responsible for muscular control
It affects children between the ages of 3 months to 6 years.
Early symptoms are a sore throat, headache, muscle pain,
Later symptoms are stiffness in the neck region, tingling sensation in the limbs.
Finally, the muscles lose the power and the limb gets thinner and deformed.
Proper hygiene should be maintained.
Proper disposal of sewage.
OPV (oral Polio Vaccine) must be given to children.
OPV contains killed or weakened virus.
As per National Immunization Schedule, a dose of polio drops is given orally to the child at 1 ½, 2 ½, and 3 ½ months age and finally, a booster dose is given at the age of 1 ½ years.
Pulse Polio Program is a largest single day public health project.
Pulse polio program is an attempt to eradicate polio from our country.
What is Meiosis?
What is a pathogen?
How do vaccines work in our body
What are weeds?
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