Cases of
WN virus disease in horses have been documented,
either by virus isolation or by detection of WN virus-neutralizing
antibodies in 1999, 2000, and 2001. Approximately
40% of equine WN virus cases results in the death
of the horse. Horses most likely become infected
with WN virus in the same way humans become infected,
by the bite of infectious mosquitoes.
Pending>>>
In locations
where WN virus is circulating, horses should be protected
from mosquito bites as much as possible. Horses vaccinated
against eastern equine encephalitis (EEE), western
equine encephalitis (WEE), and Venezuelan equine
encephalitis (VEE) are NOT protected against WN virus
infection. A West Nile virus vaccine for horses was
recently licensed, but its effectiveness is unknown.
Horses infected by WN virus develop a brief low-level
viremia that is rarely, if ever, infectious to mosquitoes.
There is no reason to destroy a horse just because
it has been infected with WN virus. Data suggest
that most horses recover from the infection. Treatment
would be supportive and consistent with standard
veterinary practices for animals infected with a
viral agent.
Pending>>>
