West Nile Virus Integration Flashcards
structure of west nile virus
single stranded RNA
negative sense
enveloped
continuous genome w/ 10 major genes
what do the 10 major genes code for
1/3 code for structural proteins
2/3 code for replication proteins (non-structural)
how does the outer surface of WNV change
changes when released
intracellular: spiked outer surface
extracellular: flat outer surface
how did WNV spread to the US
entered in New York from a closely related strain from Israel
unknown transmission - migratory birds, infected mosquitoes, illegal pets, tourists, commerce, domestic animals, etc
reservoir for WNV
all bird species
causes high mortality in American crows
vector for WNV
mosquitoes
can from from birds to mosquitoes and mosquitoes to birds
dead end hosts for WNV
humans and horses
do not achieve high enough viremia to spread to mosquitoes during a bite
what time of year is WNV most common
June through November due to mosquito transmission
where is WNV most common
Midwest
abundant in dry places due to limited water resources bringing birds and mosquitoes in close proximity
how can transmission risk be tracked for WNV
- clinical confirmed human and equine infections
- viral isolation or RNA in mosquitoes and dead birds
- sentinel chicken seroconversion (chickens do not achieve high viremia)
- wild bird seroconversion
equine WNV
- low morbidity (majority are asymptomatic)
- high mortality
WN fever: febrile, mild depression
CNS disease: depression or anxiety, ataxia, paresis, paralysis, muscle fasciculation, recumbency
- acute onset most common
WNV diagnostics
- IgM capture ELISA (differentiates infected vs vaccinated)
- PCR
WNV treatment
- supportive therapy
- anti-inflammatories
- sling
- hyperimmune plasma
prognosis is poor if CNS disease
WNV prevention
vaccination w/ annual booster in the spring
want to boost adaptive immunity right before mosquito season
