pathogens -> transmission

Question 1

What is direct transmission?

Answer 1

Pathogen is transferred directly from one individual to another.

Question 2

Types of direct contact and examples.

Answer 2

• Kissing or any contact w body fluids e.g. bacterial meningitis + STIs.
• Direct skin-to-skin contact e.g ring worm, athletes foot.
• microorganisms from faeces transmitted on the hands, for example, diarrhoea diseases.

Question 3

Types of direct transmission.

Answer 3

• Direct contact.
• Inoculation.
• Ingestion.

Question 4

Types of inoculation and examples.

Answer 4

• Through a break in the skin for example during sex (AIDS and HIV).
• From an animal bite, for example rabies.
• Through a puncture wound.

Question 5

Example of ingestion.

Answer 5

• Taking in contaminated food or drink.

Question 6

What is indirect transmission?

Answer 6

• Where the pathogen travels from one individual to another indirectly.

Question 7

Examples of indirect transmission.

Answer 7

• Fomites.
• Droplet infection.
• Vectors.

Question 8

Examples of fomites.

Answer 8

Inanimate objects such as bedding, socks, or cosmetics can transfer pathogens for example athletes foot.

Question 9

Examples of droplet infection.

Answer 9

• Minute droplets of salvia and mucus are expelled from your mouth as you talk, cough or sneeze.
• If these droplets contain pathogens, when healthy individuals breathe the droplets in they may become infected, for example influenza, tuberculosis.

Question 10

What is a vector and examples?

Answer 10

• A vector transmits communicable pathogens from one host to another.
• Vectors are often but not always animals, for example mosquitoes transmit malaria.
• Water can also act as a vector, for example diarrhoeal diseases.
• Animals such as insects and birds can act as vectors.
• Wind can act as a vector.
• Humans can act as vectors.

Question 11

What are the factors affecting transmission of communicable diseases in plants?

Answer 11

• Planting varieties of crops that are susceptible to disease.
• Over-crowding increases the likelihood of contact.
• Poor mineral nutrition reduces resistance of plants.
• Damp, warm conditions increase the survival and spread of pathogens and spores.
• Increased rainfall and wind promote the spread of diseases, changing conditions allow animal vectors to spread to new areas, direr conditions may reduce the spread of disease.