KA 5: parasitism: transmission and virulence Flashcards
1
Q
what is transmission?
A
the spread of a parasite to a host
2
Q
what is virulence?
A
the harm caused to a host species by a parasite
3
Q
how are ectoparasites transmitted?
A
direct contact
4
Q
how are endoparasites of the body tissue transmitted?
A
by vectors or by consumption of intermediate hosts
5
Q
what are two factors that increase transmission rate?
A
- 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
6
Q
why is host behaviour exploited and modified by parasites?
A
to maximise transmission
7
Q
list the alternation of host foraging
A
- movement
- sexual behaviour
- habitat choice
- anti-predator behaviour
8
Q
what does the host behaviour become a part of?
A
the extended phenotype of the parasite
9
Q
how do parasites benefit in terms of growth, reproduction and transmission?
A
parasites often suppress the host immune system and modify host size and reproductive rate
