5. transmission and virulence

Question 1

what is transmission?

Answer 1

Transmission is the spread of a parasite to a host

Question 2

what is virulence?

Answer 2

Virulence is the harm caused to a host species by a parasite

Question 3

how are ectoparasites transmitted?

Answer 3

Ectoparasites are generally transmitted through direct contact

Question 4

how are endoparasites transmitted?

Answer 4

Endoparasites of the body tissues are often transmitted by vectors or by consumption of intermediate hosts

Question 5

what factors increase transmission rates?

Answer 5

• the 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

what becomes part of the extended phenotype?

Answer 6

The host behaviour becomes part of the extended phenotype of the parasite

Question 6

what maximises transmission?

Answer 6

Host behaviour is often exploited and modified by parasites to maximise transmission

Question 7

what do parasites do?

Answer 7

Parasites often suppress the host immune system and modify host size and reproductive rate in ways that benefit the parasite growth, reproduction or transmission