Pelzer Flashcards
What is the most common arboviral disease in the US?
West Nile Virus
What type of virus is WNV?
Flavivirus
How is WNV transmitted?
mosquitos, blood transfusions, organ donations; what sucks is that blood is screened, but organs are not
What animal is the reservoir for WNV?
Passerine birds aka perching birds
What 3 species are primarily effected by WNV?
humans, horses, crows and jays
When do we see most cases of WNV (traditionally)?
late summer, early fall; but climate change…
Are humans typically asymptomatic or symptomatic with WNV?
Asymptomatic- 80%
If humans present symptomatically with WNV, what is the typical presentation?
flu like symptoms: sore throat, muscle aches, headaches, lymphadenopathy
What is the percentage of humans infected w/ WNV that are symptomatic? If they are symptomatic, what is the chance of getting the neuroinvasive form?
20%; 1:150
What population (humans) is more at risk for WNV?
> 50 yrs
How do horses present when infected w/ WNV?
fever, encephalomyelitis, muscle twitching, ataxia
How is St. Louis Encephalitis transmitted?
the damn mosquitos again
What is the reservoir for St. Louis Encephalitis?
birds
Why do we see a cluster of infections (in humans) of St Louis Encephalitis in low socioeconomic and older neighborhoods?
decreased trash collection, decreased in maintenance/ repair –> increase in breeding grounds for the mosquitos; less access to adequate medical care
Where do the annual cases of EEE occur in VA?
Tidewater area
Why does the Tidewater area see cases of EEE in VA?
fresh water swamps are breeding ground for mosquitos
Can humans get EEE?
Yes, but they are accidental hosts.
What are the clinical signs assc w/ EEE in a human?
fever, headache, vx, lethargy, aseptic meningitis, or encephalitis delirium, and coma
What population is at risk for severe disease assc w/ EEE?
Children under 15yrs and adults 50yrs>
What is the case fatality rate of those infected w/ EEE?
30%
What is the reservoir for EEE?
passerine birds AND water fowl
What population is at risk for clinical signs (in humans) in regards to WEE?
young adults and <1 yr
In what infection will a child transition from fever, headache, stiff neck, spastic paralysis, and mental confusion -> personality changes, mental retardation, and continued spastic paralysis?
WEE
What is the equine encephalitis that does not have birds as its reservoir?
VEE
VEE: what is the reservoir for endemic strains? epidemic strains?
endemic: rodents and mosquitos; epidemic: horses and mosquitos
VEE: Is direct human transmission possible?
Yes! virus was present in pharynx of 40% of human cases
Where do we see cases of Equine Hendra virus?
Australia
What is the viral agent of equine hendra virus?
henipavirus
What is the reservoir of equine hendra virus?
the damn fruit bats
Equine Hendra virus:How do we think horses are exposed?
Bats are feeding on the fruit in trees; horses are underneath or in passing when bats urinate and thus pick up the organisms
Equine hendra virus: how do humans get the virus?
it MUST go through the horse in order to get to the human
What virus in horses leads to acute respiratory syndrome followed by death in 1-3 days?
Equine hendra virus
What symptoms present in a human with equine hendra virus?
flu-like symptoms that worsen/ progress; 60% fatality rate
How many cases do we see nationally from horses w/ rabies?
40 annually
what are the strains of rabies virus?
fox, skunk, raccoon, bat
What animals are considered at risk when raccoon rabies are established?
non-carnivores like opossums, groundhogs, and beavers because they share the same eco-niche
what are the clinical signs of rabies in horses?
“paralytic” and “dumb”; rubbing of bite site
what sucks about vaccinating a horse for rabies?
it gives the owner a false sense of security
Why is vesicular stomatitis reportable?
It resembles foot and mouth
where does vesicular stomatitis occur?
4 corners
T or F: vesicular stomatitis is only found in the Americas
True
what is the route of transmission for vesicular stomatitis?
midges (and sand flies) and black flies (SubQ or mucosal)
What is the viral agent of vesicular stomatitis?
rhabdovirus, vesciulovirus; serotypes of Indiana and NJ