2q- Transmission and virulence

Question 1

What is transmission?

Answer 1

The spread of a parasite to a host

Question 2

What is virulence?

Answer 2

The harm caused to a host species by a parasite

Question 3

How are ectoparasites generally transmitted?

Answer 3

Through direct contact or by consumption of intermediate hosts

Question 4

How are endoparasites often transmitted?

Answer 4

Through vectors (e.g. mosquito carrying malaria)

Question 5

What are two factors that increase transmission rates?

Answer 5

• the overcrowding of hosts when they are at a high density
• mechanisms, such as vectors and waterborne dispersal stages, that allow the
  parasite to spread even if infected hosts are incapacitated

Question 6

What is often done by parasites to maximise transmission?

Answer 6

Host behaviour is exploited and modified

Question 7

What are examples of host behaviours which are altered by parasites?

Answer 7

Host foraging, movement, sexual behaviour, habitat choice or anti-predator behaviour

Question 8

What does the behaviour of the host which has been altered become?

Answer 8

Part of the extended phenotype of the parasite

Question 9

What do parasites often do to benefit their growth reproduction or transmission?

Answer 9

Suppress the host immune system, and modify host size and reproductive rate