N.Y. Officials Encourage Equine EEE, WNV Vaccinations

New York State Agriculture Commissioner Darrel J. Aubertine has urged horse owners across New York State to vaccinate their horses against Eastern equine encephalitis (EEE) and West Nile virus (WNV). This is especially important since parts of New York have mosquito activity into late November.

Aubertine is reminding horse owners to vaccinate against these diseases due to recent cases of EEE found in horses in St. Lawrence and Westchester Counties, along with a case of WNV found in a horse in Saratoga County. The state Department of Agriculture and Markets has made veterinarians across the state aware of these confirmed cases.

"While these diseases can be fatal among horses, they are also largely preventable," said Commissioner Aubertine. "I encourage all horse owners in the state to act responsibly and make sure your horses receive proper vaccinations. If you have questions about equine vaccinations and the health of your horse, contact your local veterinarian immediately."

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

A viral disease, the fatality rate in horses is 75-95%. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care. Horses that survive might have long-lasting impairments and neurologic problems. Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures.

Clinical signs for WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations (twitching); hyperesthesia (hypersensitivity to touch and sound); changes in mentation (mentality), when horses look like they are daydreaming or "just not with it"; occasional somnolence (drowsiness); propulsive walking (driving or pushing forward, often without control); and "spinal" signs, including asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia. Equine mortality rate can be as high as 30-40%.

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 their local health department. The State Department of Agriculture and Markets has been working closely with local health departments on the three confirmed cases this year.

Vaccines are available to drastically reduce the incidence of EEE and WNV in horses. The vaccines can be effective for six to twelve months and horses should be re-vaccinated at least annually. In an area 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.

Other prevention 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.

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