Agriculture
Secretary Art Brown Jr. said today that the death
last week of a six-year-old Thoroughbred gelding
in Tuckahoe, Cape May County, has been attributed
to infection with the West Nile virus (WNV), in
conjunction with other medical complications. According
to State Veterinarian Dr. Ernest Zirkle, the horse
became ill on August 27, showing signs of neurological
deficits, weakness, an elevated temperature of
104 F and difficulty rising, all possible signs
of equine encephalitis. The horse had not left
the farm for the past three months. The horse was
euthanized on August 30. Samples from the horse
were tested at NJDA's animal health laboratory
for both Eastern and Western equine encephalitis
as well as equine infectious anemia and WNV. Because
the animal had demonstrated some uncharacteristically
aggressive behavior, the laboratory at the Department
of Health and Senior Services (DHSS) also tested
samples for rabies. Preliminary results from this
group of tests revealed an elevated titer that
was later confirmed as WNV by the National Veterinary
Services Laboratory (NVSL) in Ames, Iowa.* Of the
diseases tested for, the results confirmed the
presence of WNV only. Horses become infected with
the WNV when infected mosquitoes bite them. The
disease cannot be spread from horse to horse or
from an infected horse to humans or domestic pets.
Not all horses that contract WNV become ill. Last
year, 25 horses on Long Island were clinically
ill with neurological signs and there was evidence
of WNV infection. Nine of those horses died or
were euthanized. However, samples from clinically
normal horses that were stablemates of the affected
horses showed that more than one-quarter of them
had also been infected with WNV but never exhibited
any symptoms of the illness. This year, the first
horse diagnosed with WNV was located on Staten
Island. Since then, a horse in Rhode Island has
been diagnosed with the disease. In cooperation
with the state Department of Environmental Protection,
DHSS and USDA, NJDA has launched a proactive campaign
to educate horse owners about the precautions they
must take to decrease mosquito habitat, virtually
the only way horse owners can minimize the chance
of an animal being stricken with WNV. Recommended
actions include decreasing mosquito habitats near
homes and stable areas by emptying standing water
from cans, tires, swimming pool covers, clogged
gutters or other reservoirs which can serve as
mosquito breeding sites and by frequently changing
the fresh water in drinking troughs to prevent
them from becoming breeding sites Although there
is no preventive vaccine for WNV, equine encephalitis
is a reportable disease in New Jersey and is treated
symptomatically. Concerned horse owners should
contact their veterinarians for additional information
or consultation about specific cases of illness
in their animals. Last week, DHSS revealed that
a 43-year old Jersey City man had tested positive
for WNV. He is recuperating at home. To date, 496
birds (495 crows and a cockatiel) found in 10 counties
have tested positive for the presence of WNV. Positive
birds have been found in Bergen (122), Essex (63),
Hudson (48), Mercer (1), Middlesex (114), Monmouth
(54), Morris (6), Passaic (36), Somerset (2) and
Union (50) Counties. A total of 1,077 crows have
been accepted for testing this year. A total of
five mosquito pools collected in Bergen County
have tested positive for the presence of WNV. More
than 1,400 mosquito pools from all 21 counties
have been collected by the Rutgers Mosquito Research
and Control Unit and tested by DHSS and/or the
Centers for Disease Control and Prevention (CDC).
Blood samples taken weekly from sentinel chicken
flocks placed in all 21 counties and tested by
NJDA have all been negative for the presence of
WNV to date. And blood samples of 1,115 house sparrows
collected in Bergen, Passaic and Sussex Counties
and tested by the CDC also did not detect WNV.
For more information on WNV or mosquito spraying,
or to report dead birds and areas of standing water
where mosquitoes breed, residents should call their
local or county Departments of Health and mosquito
control agencies or visit the web sites maintained
by DHSS (www.state.nj.us/health),
DEP (www.state.nj.us/dep/mosquito),
the CDC (www.cdc.gov),
and NJDA (www.state.nj.us/agriculture/westnile.htm). _______________________________
* Tests reported by NVSL included a strongly positive capture ELISA
WNV IgM, indicating recent exposure to the virus; a positive RT-PCR
test (reverse transcriptase polymerase chain reaction) identifying
WNV RNA sequences in the brain of the horse; and a specific WNV antibody
response as demonstrated by PRNT (plaque reduction neutralization test).
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