1. Tuberculosis

Pathogen: A bacterium (Mycobacterium tuberculosis)

Mode of transmission: airborne-discharged through sputum, cough and sneeze, of the infected person.

Incubation period: 2-10 weeks during which the bacteria produce a toxin, tuberculin.


  1. Persistent fever and coughing.
  2. Chest pain and blood comes out with the sputum.
  3. General weakness.

Prevention and Cure

  1. Isolation of patient to avoid spread of infection.
  2. BCG vaccination is given to children as a preventive measure.
  3. Living rooms should be airy, neat and with clean surroundings.
  4. Antibiotics be administered as treatment.

2. Typhoid

Pathogen: A Bacillus rod-shaped bacterium (Salmonella typhi)

Mode of transmission: Through contaminated food and water

Incubation period: About 1-3 weeks


  1. Continuous fever, headache, slow pulse rate.
  2. Reddish rashes appear on the belly.
  3. In extreme cases, ulcers may rupture resulting in death of the patient.

Prevention and Cure

  1. Anti-typhoid inoculation should be given.
  2. Avoid taking exposed food and drinks.
  3. Proper sanitation and cleanliness should be maintained.
  4. Proper disposal of excreta of the patient.
  5. Antibiotics should be administered.

3. Cholera

It often breaks out among people in crowded areas and the areas with poor sanitary conditions.

Pathogen: Comma shaped bacterium (Vibrio cholerae)

Mode of transmission: Contaminated food and water. Housefly is the carrier.

Incubation period: 6 hours to 2-3 days


  1. Acute diarrohoea and watery stool.
  2. Muscular cramps.
  3. Loss of minerals through urine.
  4. Dehydration leads to death.

Prevention and Cure

  1. Cholera vaccination should be given.
  2. Electrolytes (Na, K, sugar) dissolved in water should be given to the patient to check dehydration (ORS–oral rehydration solution).
  3. Proper washing and cooking of food.
  4. Proper disposal of vomit and human excreta.
  5. Flies should not be allowed to sit on eatables and utensils.

4. Diphtheria

This disease generally occurs in children of 1-5 years of age.

Pathogen: Rod-shaped bacterium (Cornybacterium diphthereae)

Mode of transmission: Through air (droplet infection)

Incubation period: 2-4 days


  1. Slight fever, Sore throat and general indisposition.
  2. Oozing semisolid material in the throat which develops into a tough membrane. The membrane may cause clogging (blocking) of air passage, resulting into death.

Prevention and Cure

  1. Immediate medical attention should be given.
  2. Babies should be given DPT vaccine.
  3. Sputum, oral and nasal discharges of the infected child should be disposed off.
  4. Antibiotics may be given under doctor’s supervision.
  5. Isolation of the infected child.

5. Leprosy

Pathogen: A bacterium (Mycobacterium leprae)

Mode of transmission: Prolonged contact with the infected person. Nasal secretions are the most likely infectious material for family contacts.

Incubation period: 1-5 years


  1. Affects skin.
  2. Formation of nodules and ulcer.
  3. Scabs and deformities of fingers and toes.
  4. Infected areas lose sensation.

Prevention and Cure

  1. The children should be kept away from parents suffering from leprosy.
  2. Some medicine may arrest the disease and prevent from spreading.