Veterinary Submission and Testing for West Nile Virus in Horses
University of Minnesota Veterinary Diagnostic Laboratory
Case reporting - All
clinical cases of central nervous system (CNS) disease in horses must be
reported by telephone to the Minnesota Board of Animal Health
at 651-296-2942. Laboratory results will be reported to the Board by the
laboratory where the tests are completed.
Diagnosis - The introduction of WNV into Minnesota has actually made diagnosis
of CNS disease in horses much more complicated. In the past, the differential
diagnosis for CNS cases in horses primarily included rabies, the equine arbovirus
encephalitides (Eastern, Western, and Venezuelan encephalomyelitis) and equine
herpes virus. We must now be careful not to assume that every CNS case in
a horse is WNV. If we become complacent, we stand the risk of missing cases
of rabies
and arbovirus encephalitis - all of which can have significant public health
implications.
Rabies should always be our first differential for CNS cases in horses. If
a horses dies with CNS signs and there is any possibility of human exposure,
the
brain should be submitted for rabies testing.
Sample submission procedures - All samples can be sent to the University
of Minnesota Veterinary Diagnostic Laboratory (VDL). The laboratory will
run the IgM ELISA
test for WNV on horses. The VDL currently cannot test samples from
animals other than horses. During the mosquito season, the test is run Tuesdays and
Thursdays
with results available on Wednesdays and Fridays. Brain tissue submitted
to the VDL will be processed and then forwarded to the Minnesota Department
of Health
(MDH). MDH will test the samples for rabies and if negative, they will be
tested for WNV and other arbovirus encephalitides.
Fees for testing - The Minnesota Veterinary Diagnostic Laboratory will charge
$4.75 for the serum IgM ELISA. Lab fee for brain tissue examination, without
human exposure, is $25.00. There is no charge for examination of brain tissue
with possible human exposure to rabies.
NVSL will be charging $7.75 for serum neutralization test (This test is used
for testing nonequine samples or for determining post vaccination titers.),
$7.50 for HI test, and $59.00 for PCR tissue tests for West Nile Virus and
Eastern
Equine Encephalitis.
For more information, call the University of Minnesota Veterinary Diagnostic
Laboratory at 612-625-8787.