Chapter 14: Evolution and Human Health

Polio

Evolves to infect the CNS which kills the host so the parasite doesn't gain transmission as a result

Tetanus

________ produces a neurotoxin, a result of selection in the life in the soil, not the host.

Influenza Antigenic Shift

________: gradual accumulation of mutations allows hemagglutinin to escape neutralizing antibodies.

Transmission

________ requires opportunities for pathogens to spread to a new host.

the damage inflicted by a pathogen on its host

Virulence

harms the host

Costs of virulence

increase pathogen reproduction

Benefits of virulence

virulence in one host is a by-product of selection on other traits

Coincidental evolutionary theory

The pathogen enjoys short-term advantages in survival and reproduction but speeds up the death of the host

Short-sight evolution hypothesis

there is a trade-off between transmission and virulence

Trade-off hypothesis

Vertical Transmission

(HIV, some STIs) transmitted from parent to offspring, the host must live to reproduce

low virulence

Vertical transmission favors...

Horizontal Transmission

Spread to any other individual rapidly

high virulence

Horizontal transmission favors...

Water or Vector-borne pathogens

rapidly spread without contact between hosts

high virulence

Water or Vector-borne pathogens favor...

Direct Transmission

Direct contact is required between hosts for transmission, the host must remain active

low virulence

Direct transmission favors...