Lecture 44 - Viral zoonosis Flashcards
Define:
cross-species transmission
passage of virus between hosts belonging to different species
T/F: cross-species transmission and spillover are the same
TRUE
Define:
zoonosis
transmission of virus from animals to humans
what is a reservoir host
wild vertebrae animal that disease lives in
what is an intermediate host
wild or domesticated vertebrae animals
what are vector hosts
biting arthropod animals
describe a stable host-virus interaction
maintains virus in ecosystem
describe an evolving host-virus interaction
passage of virus to a population that has not seen that virus before
describe a dead-end host-virus interaction
one way passage of virus to different species; usually means killing host to end virus
describe a resistant host-virus interaction
infection is blocked
why are there no listed examples of resistant host-virus interactions for spillover
if an interaction is resistant, infection is blocked and thus nothing can be documented
define one health
idea that health of people is connected to the health of animals and our shared environment
what 5 factors contribute to virus spillover
- predator-prey interactions
- bats
- mosquito vectors
- forced species interactions
- ecological and anthropogenic activities
summarize predator-prey interactions and their contribution to spillover
contact with bodily fluid in wounds, inhalation, or ingestion and failure of predator immune barriers
ex: SIV, HIV
T/F: bats harbor more zoonotic viruses than any other species
TRUE
why are bats good reservoir species
they have a constitutively active antiviral response to suppress viruses that allows them to replicate rapidly without killing host
what 3 host defenses do bats have
- constitutive expression of interferons
- increased expression of heat-shock proteins
- increased autophagy
what 2 immune tolerances do bats have
- suppressed pathogen sensing
- suppressed inflammasome pathways
what are arboviruses spread by
by vector insects
what are the 3 transmission modes of arboviruses
- urban epidemic cycle (human-vector-human)
- enzootic cycle (direct spillover from natural hosts)
- epizootic cycle (amplification in domestic animals)
what is a wet market? what are the zoonotic implications?
market where animals are slaughtered upon order; spillover is common due to housing and sanitation
T/F: exotic animal trade can also lead to virus spillover
TRUE
what are ecological examples that may cause spillover
drought, fire, hurricane
what are anthropogenic examples that may cause spillover
urbanization, air travel, pollution, transport of animals
