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 – Why do we fall ill out for 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
- 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.
Symptoms
- 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).
Prevention
- 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
Control
- Quinine – which is an extract from the cinchona tree is used to manufacture chloroquine. This drug kills the malarial parasite.
Influenza (flu)
- This is an airborne disease caused by a virus called
- It spreads through droplet infection.
- The virus attacks the mucous membrane of the nose.
Symptoms
- Running nose, sneezing, coughing, body ache, and fever are some of the symptoms of this disease.
Prevention
- Avoid physical contact with patients suffering from
Control
- 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 (Hepatitis)
- 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.
Prevention
- 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
Control
- 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
Rabies (Hydrophobia)
- 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.
Symptoms
- 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.
Prevention
- 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.
Control
- 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
- 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:
- Sexual intercourse
- Sharing needles to inject drugs
- Blood transfusion
- From HIV positive mother to unborn child
- Razor at the hairdressing saloon
Symptoms
- 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
Prevention
- 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.
Tuberculosis (TB)
- 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
Symptoms
- 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-
- Pulmonary T.B.
- 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.
- Swelling of lymph glands
Prevention
- 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
Control
- ATT (Anti-tubercular therapy) should be administered.
- Streptomycin (antibiotic) is an effective drug.
Cholera
- 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.
Symptoms
- 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.
Prevention
- 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.
Control
- Immediate medical help is required to control the disease.
- Tetracycline (antibiotic) is effective in controlling cholera.
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Typhoid
- 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.
Symptoms
- 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
Prevention
- Proper sanitation
- Control of flies
- Anti typhoid vaccines.
Control
- Ciproflox Is the most drug used.
Diarrhoea
- 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.
Symptoms
- 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
Prevention
- 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
Control
- 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
Polio
- 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.
Symptoms
- 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.
Prevention
- 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.
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