Vaccinate Equine for mosquito-borne diseases
Mosquitoes pose a threat to humans and a deadly danger to horses and mules. This is due to the potential to transmit two mosquito borne illnesses, West Nile Fever and Eastern Equine Encephalomyelitis, both found in North Carolina. Fortunately for horses and mules, there are approved vaccinations to help protect them against each of these diseases.
In 2002, the State Veterinarians office confirmed West Nile Virus infection in 29 equine across NC. Positive cases were found in Alamance, Beaufort, Brunswick, Currituck, Dare, Davidson, Duplin, Edgecomb, Gates, Iredell, Johnston, Nash, New Hanover, Pasquotank, Pender, Randolph, Robeson, Rutherford, Stanly, Surry, and Warren counties. The West Nile
Virus was confirmed in 76 counties through tests done on birds or mosquito pools, and is considered to be established in all regions of the state.
It is clear that West Nile is here to stay. In 40 states across the nation, a total of 14,717 equine were diagnosed with West Nile Virus last year, including every state bordering North Carolina and east of the Mississippi River.
Unvaccinated horses require two doses of the West Nile vaccine, given three weeks apart. Booster shots should be given at least annually, and possibly more often depending on the vaccination protocol prescribed by a veterinarian. The vaccination does not fully protect the animal until at least 3 to 6 weeks after the second booster shot.
Symptoms of WNV in horses can include loss of appetite and weakness or paralysis of hind limbs, convulsions, impaired vision or hyperexcitability.
Eastern Equine Encephalomyelitis (EEE), has already been confirmed in four horses in three counties in NC. The early confirmation of the disease this year, which isn't usually found until August, is troubling to veterinarians and public health officials because it indicates that the disease may be widespread in the state.
EEE, often referred to as "sleeping sickness," has been confirmed in horses in Cumberland, Pender and Onslow counties. The unusually wet weather we have experienced since last fall has spawned heavy populations of mosquitoes, which are the primary transmitters of this
disease, Early indicators show that this could be the worst year we have had for EEE since 2000 with 18 confirmed cases. It is imperative that horse owners vaccinate their animals against this deadly disease. Already this year, South Carolina, and Georgia have confirmed dozens of cases and Florida has seen an explosion of cases.
Signs or symptoms of EEE in horses are usually noticed about five days after an infected mosquito bites them. Initially, horses are depressed and quiet. Other signs include impaired vision, aimless wandering, head pressing, circling, inability to swallow, krregular staggering gait, paralysis, convulsions, and death. Most deaths occur within two to three days after symptoms appear. The symptoms of EEE are similar to those of rabies, making it essential that a definitive diagnosis is made.
There is no specific treatment for animals affected with EEE, making vaccinations essential to the prevention of the disease. The vaccination protocol consists of two vaccine injections 30 days apart, followed by booster shots every six months, preferably in the early spring and late summer or early fall.
The threat is real, so all equine owners can help protect their animals by vaccinating against West Nile and EEE. Consult a veterinarian about the appropriate vaccination program.
Protect yourself, limit your mosquito exposure through the use of repellents and protective stabling practices, particularly during the late afternoon and evening hours when mosquitoes are especially active. Also eliminate sources of standing water on their premises, which serve as breeding areas for mosquitoes.
For more information about EEE, WNV and more mosquito prevention tips, go to:
West Nile Virus - North Carolina
Feb 28, 2005
Contact: Dr. David Marshall
Mosquito season is around the corner; equine owners should consider vaccinations to protect animals.
RALEIGH - The cold weather won't last forever and mosquitoes will soon be
back, bringing with them the risk of disease. The best way to protect both
humans and animals is to reduce the breeding grounds for mosquitoes and
reduce exposure. Equine owners can protect their animals from two diseases
that are now endemic in North Carolina, West Nile Virus and Eastern Equine
Encephalomyelitis, with an easy vaccine protocol.
Horse owners should talk with their veterinarians to determine the best
time to start the vaccination process. Both vaccinations initially require
two shots, 30 days apart. Neither vaccination fully protects the animal
until after the second booster shot, so it is best to vaccinate before the
mosquito season begins. State Veterinarian Dr. David Marshall recommends a
booster shot of each vaccine be given every six months in North Carolina
because of the extended active mosquito season.
The number of confirmed cases dropped significantly in 2004. Only three
equine WNV cases and five EEE cases were confirmed in 2004 compared with
126 cases of WNV and 114 cases of EEE in 2003. State officials credit the
decrease in cases to a number of factors, including an increased number of
vaccinations, increased natural immunity among healthy horses and weather
conditions. Marshall cautions equine owners against letting their guard
down based on a one-year decline in cases. "The best way to prevent these
possibly fatal diseases is to vaccinate against them. It is inexpensive and
I encourage horse owners to continue to take measures to protect their
Symptoms of WNV in horses can include loss of appetite and depression,
fever, weakness or paralysis of hind limbs, convulsions, impaired vision,
Symptoms of EEE, also known as “equine sleeping sickness” include impaired
vision, aimless wandering, head pressing, circling, inability to swallow,
irregular staggering gait, paralysis, convulsions and death. People, horses
and birds can become infected from a bite by a mosquito carrying the
diseases, but there is no evidence that horses can transmit the virus to
other horses, birds or people through contact.
Mosquitoes can breed in any puddle that lasts for more than four days, so
removing any source of standing water can reduce the chance of exposing
animals to WNV or EEE. Keeping horses in stalls at night and using insect
screens and fans and turning off lights after dusk can also help reduce
exposure to mosquitoes. Insect repellants can be effective if used according to manufacturers’ instructions.
For more information on West Nile Virus or EEE, go to the N.C. Department
of Agriculture and Consumer Services’ Veterinary Division Disease Alerts
Web page at www.ncagr.com/vet/DiseaseAlerts.htm
North Carolina State University
College of Agriculture and Life Sciences
North Carolina Cooperative Extension,
Rockingham County Center
525 NC 65, Suite 200, Reidsville, NC 27320
Phone : (336) 342-8235 Fax: 336-342-8242
Email : firstname.lastname@example.org
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