WNV not going away

East Lansing, Mich. - The West Nile Virus (WNV), which adversely affects a horse's neurological system, has been found in 18 states and Ontario, since it was first discovered in New York in 1999.

"Within a couple of years, WNV will be nationwide, so we should treat this virus as if it's here to stay," says Dr. Judy Marteniuk, MSU extension veterinarian and large animal clinician, Michigan State University College of Veterinary Medicine.

Although horses are considered "dead-end hosts," the virus can cause ataxia, somnolence, dullness, listlessness, facial paralysis and inability to rise, according to Dr. John Berends, equine reproductive specialist and MSU Extension veterinarian.

There is no specific treatment, according to Berends. Marteniuk adds, "Prevention remains the best practice..."

Although Fort Dodge Animal Health released a safe killed vaccine for WNV last August, its effectiveness has not yet been proven. Preliminary data seems to support a need for two vaccinations initially.

"Horses have developed disease after only one vaccination, and a few have developed disease within two weeks after the second vaccination," says Marteniuk. After this time, horses appear to be protected.