Question

1. What is an infectious disease?
2. What are the different means by which they spread?
3. What precautions can you take to reduce the incidence of infectious disease?

Answer 1

1. Infectious disease:

1. These diseases spread from one person to another through the air, water, food, insects, and physical contact.
2. These diseases are caused by microorganisms or pathogens such as bacteria, fungi, viruses, and protozoa.
3. For eg- Tuberculosis, AIDS, malaria, etc.

2. Transmission of disease:

(i) Direct transmission- In direct transmission, pathogens are transferred from an infected person to a healthy person directly such as chickenpox, smallpox, and measles. Intimate physical contact or sexual act results in the transmission of diseases such as syphilis, and AIDS.

1. Contact with soil- tetanus causing bacteria enter through cuts and injury on the skin.
2. Through animal bites- rabid dogs and monkeys spread the rabies virus through their bites
3. Transplacental transmission- some diseases like syphilis and AIDS can be transmitted from an infected pregnant woman to her fetus through the placenta.

(ii) Indirect transmission- when the pathogens of some diseases enter the human body through some intermediate agents, i.e. they enter indirectly.

1. Through air- When an infected person coughs or sneezes that results in the discharge of small droplets carrying pathogens. When others around him inhale these droplets, the pathogens enter their body.
2. Through contaminated food and water- insects such as flies, and cockroaches carry disease-carrying germs and contaminate the food that is kept open. Water-borne diseases occur when drinking water gets mixed with sewage or other pollutants.
3. Through fomites- fomites are nonliving articles or objects used by an infected person such as clothes, handkerchiefs, towels, etc. These articles are capable of carrying and transferring pathogens from one person to another.
4. Through vectors- the carrier of pathogens or diseases is called vectors. For eg- in malaria, female anopheles is a vector.

3. Precautions to prevent infectious diseases-

1. Wash your hand regularly.
2. Stay at home if you are sick.
3. Cover your mouth and nose when you cough and sneeze to avoid infecting others.
4. Practice food safety.
5. Practice safe sex.
6. Get immunized against infectious diseases such as chickenpox, etc.
7. Sanitise the surface regularly.
8. Ventilate your home and working place.