4.1.1: Communicable Diseases: Modes Of Transmission

Question 1

What is the definition of inoculation?

Answer 1

The introduction of a pathogen into the body to stimulate an immune response

Inoculation can be done through vaccines or direct exposure to pathogens.

Question 2

What are droplets in the context of disease transmission?

Answer 2

Pathogens transmitted in droplets of water, e.g. saliva and mucus expelled when sneezing

Droplets can travel short distances and infect individuals nearby.

Question 3

What are fomites?

Answer 3

Inanimate objects that can carry and transmit pathogens, such as dirty bedding, socks, and cosmetics

Fomites can harbor pathogens and contribute to indirect transmission.

Question 4

List the modes of direct transmission.

Answer 4

• Direct contact - touching, kissing, contact with cuts in skin and sexual contact
• Inoculation - animal bites, sharing needles and cuts in skin
• Ingestion - drinking and eating contaminated water and food

These modes involve direct interaction with infected individuals or materials.

Question 5

What is meant by indirect transmission?

Answer 5

Transmission of pathogens through intermediaries, such as vectors or fomites

Indirect transmission does not require direct contact with an infected individual.

Question 6

What are vectors in disease transmission?

Answer 6

Usually animals that pass the pathogen to humans, such as mosquitoes transmitting malaria

Vectors play a crucial role in the lifecycle of many pathogens.

Question 7

How can contaminated soil contribute to disease transmission in plants?

Answer 7

Pathogens and their spores can remain in the soil and infect the roots of subsequent plants

Examples include tobacco mosaic virus and black sigatoka.

Question 8

What factors can increase the likelihood of disease transmission?

Answer 8

• Hot climates - pathogens can thrive due to increased kinetic energy
• Social factors - poverty, poor sewage infrastructure, lack of fresh water and food, poor sanitation, overcrowding

These conditions can facilitate the spread of communicable diseases.

Question 9

True or False: Direct contact is the only mode of transmission for communicable diseases.

Answer 9

False

There are multiple modes of transmission, including indirect methods.

Question 10

Fill in the blank: _______ can carry pathogens and spores from one plant to another.

Answer 10

[Vectors]

Vectors include wind, water, animals, and humans.

Question 11

What is direct transmission in the context of plant disease?

Answer 11

Direct contact between different plants

This can occur through physical contact or shared soil.