N.Y. Owners Encouraged to Vaccinate Horses against Diseases

N.Y. Owners Encouraged to Vaccinate Horses against Diseases

Vaccines must be handled and administered properly, prior to an anticipated increase in mosquito activity in a local area, to be effective. New York State Veterinarian David Smith, DVM, recommends that the vaccines be administered by a veterinarian.

Photo: Anne M. Eberhardt/The Horse

State Agriculture Commissioner Darrel J. Aubertine; State Health Commissioner Nirav R. Shah, MD, MPH; and State Gaming Commission Acting Director Robert Williams urged horse owners across New York state to vaccinate their horses against Eastern equine encephalitis (EEE) and West Nile virus (WNV). In 2012, two cases of EEE were reported in horses in New York, as well as seven WNV cases. No confirmed cases of either disease have been reported in New York horses thus far in 2013.

“Every year in New York, cases of Eastern Equine Encephalitis and West Nile Virus pop up in horses across the state—diseases which are largely preventable,” said Aubertine. “Good prevention programs are a key component to any animal health plan and I encourage horse owners across New York to take the necessary precautions and vaccinate their horses against these diseases today.”

While it is preferable to vaccinate horses against these diseases in the spring before the mosquitoes that transmit them are active, early summer is not too late; New York often has mosquito activity into the month of November. Vaccines for EEE and WNV can be effective for six to twelve months, and horses should be revaccinated at least annually. In areas where the diseases occur year round, many veterinarians recommend vaccinations every six months. For the vaccine to be effective, it must be handled and administered properly, prior to an anticipated increase in mosquito activity in a local area. For these reasons, state veterinarian David Smith, DVM, recommends that the vaccines be administered by a veterinarian.

Other preventative methods include eliminating standing water breeding sites for mosquitoes, using insect repellents, and removing animals from mosquito-infested areas during peak biting times, usually from dusk to dawn. In addition, water in troughs and buckets should be changed at least twice a week to discourage mosquito breeding.

There is no human vaccine for EEE or WNV. The best way to protect yourself is to keep mosquitoes from biting you. EEE is rare but serious and can affect both people and horses. Five cases have been diagnosed in humans in New York since 1971 and all have been fatal. Prior to 2009, there had not been a human case detected in the state in more than 25 years.

WNV is more common than EEE and can also cause serious illness or, in some cases, death. Not all mosquitoes carry WNV, but human cases have been reported in counties across the State. In 2012, there were 107 reported human cases of WNV statewide, nine of which were fatal.

“In addition to the health risks posed to the general public, West Nile virus and EEE can cause serious problems for horses and their owners and handlers in New York State,” said Shah. “Thankfully there is an inexpensive vaccine to protect horses, but their handlers should also take appropriate precautions to protect themselves from mosquito bites.”

To greatly minimize exposure to WNV and EEE, the New York State Department of Health recommends that people take precautionary measures, such as wearing shoes, socks, long pants, and a long-sleeved shirt when outdoors for a long period of time. People are also advised to apply appropriate mosquito repellent according to the label’s instructions and to remove all standing water from their property.

Horsepersons working at New York racetracks, where large concentrations of horses are stabled, should especially heed the recommendation to have horses vaccinated and take necessary precautions to reduce the risk of EEE or WNV. The New York State Gaming Commission’s on-track staff is monitoring facility conditions and working with track management to reduce mosquito-infested areas.

“An additional ounce of prevention goes a long way to protecting equine athletes,” said Williams. “We will continue to partner with our colleagues at the Department of Agriculture and Markets and track operators to make sure that horses are kept in the safest environment possible.”

Humans cannot become infected by handling or being exposed to an infected horse, and affected horses cannot spread either virus to other horses, people, or pets. Mosquitoes transmit both diseases from birds to horses.

Typical clinical signs of EEE in equids include staggering, circling, depression, loss of appetite, and sometimes fever and blindness. Clinical signs of WNV in horses include lethargy, weakness in the hind quarters, stumbling, lack of awareness, head tilt and head twitching, convulsions, circling, partial paralysis, and coma. Horses suffering from neurologic problems must always be handled with extreme caution, since they can be unpredictable and there is also the possibility that rabies—which can be transmitted from horses to humans—could be the cause.

Horses exhibiting neurologic signs like those listed above need to be promptly reported by veterinarians to the State Department of Agriculture and Markets’ Division of Animal Industry at 518/457-3502, in addition to the local health department.

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