West Nile Virus (WNV) causes encephalitis in birds, horses and
humans.
The virus is transmitted
from infected birds by mosquitoes. Humans and horses appear
to be especially susceptible. Studies done by the U.S.
Department of Agriculture show that infected horses will not
transmit WNV to other horses or to people. However care
should be taken when handling blood from suspect animals. Symptoms of disease caused by WNV
may include the following:
- Flu-like signs (fever and
depression)
- Skin twitching, especially around
the muzzle.
- Hypersensitivity to touch and
sound
- Driving or pushing forward without
control
- Incoordination
Because permanent neurological
problems and death can occur, early recognition and initiation of
treatment is important. No specific treatment protocol exists
however most cases will resolve with supportive therapy and
anti-inflammatories.
Efforts to prevent disease in
horses caused by WNV is through the use of the West Nile Vaccine
from Fort Dodge Pharmaceuticals and through actions that will
reduce exposure to mosquitoes. The vaccine is safe and
appears to be effective. AAEP vaccination guidelines recommend
vaccinating twice a year in the Long Island area.
The most effective way to limit the
mosquito population is to destroy the mosquito larval
habitat. This is done by reducing the amount of standing
water. Water troughs should be cleaned at least once a
week. Keeping weeds trimmed and lawn mowed help eliminate
areas where mosquitoes rest. Directly protecting horses from
mosquito bites is more difficult. Fly and mosquito repellents
may be helpful. Products containing pyrethroids are
considered safe for horses. Spray stalls, aisle walls
and other areas such as under shade trees where horses
congregate. Fans can also be used to discourage mosquitoes
from residing in your barn.
