West Nile virus is on the rise nationwide with more than 1,100 human cases reported as of Aug. 22, the highest at this point in the season since the virus was first detected in the United States in 1999. The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service National Animal Health Surveillance System reported fewer than 100 equine cases as of Aug. 18. In Kentucky the virus has been diagnosed in four horses since Aug. 2. One human case has been documented in Henry County and one in Clermont County, Ohio, just across the river from Campbell County.

"We are still in the high risk part of the season for West Nile infection," said Craig Carter, DVM, PhD, Dipl. ACVPM, director of the University of Kentucky Veterinary Diagnostic Lab (UKVDL). "The first case was diagnosed at the Breathitt Veterinary Center back on Aug. 2."

Carter said infected horses present with ataxia, which is a lack of voluntary coordination of muscle movements. Other clinical signs might include blindness, loss of motion in the hind limbs, circling, falling, and anorexia.

"As a horse owner or veterinarian, good surveillance is the key," he said. "Watch for a horse with neurological signs. Vaccination is not perfect, but it can often prevent and/or mitigate the illness. The good news is there is no evidence of person-to-person or animal-to-person infection. People are infected by the bite of a mosquito. Of course, you must always keep rabies in the back of your mind when dealing with animals that present neurological signs