2.4.3 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

Question 4

how are endoparasites of the body tissues often transmitted

Answer 4

by vectors or by the consumption of intermediate hosts

Question 5

what are factors that increase transmission rates

Answer 5

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

Question 6

why is host behaviour often exploited and modified by parasites

Answer 6

to maximise transmission

Question 7

what are examples of host behaviour modification

Answer 7

alteration of host foraging, movement sexual behaviour, habitat choice or anti predator behaviour

Question 8

what does host behaviour become

Answer 8

part of the extended phenotype of the parasite

Question 9

how do parasites benefit the parasite growth, reproduction or transmission

Answer 9

by suppressing the host immune system, modifying host size and modifying the host reproductive rate