The first horse confirmed to have West Nile virus (WNV) in Kentucky is a 3-year-old Quarter Horse filly which was bred and raised in Bourbon County, Kentucky. Bourbon County is northeast of Lexington, and Paris is one of the largest cities in the county.

Dr. Nathan Slovis, an internal medicine specialist at the veterinary firm of Hagyard-Davidson-McGee in Lexington, had the filly referred to him at the clinic on Aug. 25. The filly first began showing neurologic signs on Aug. 23. The filly was in training for arena events (not racing), and she had been kept stabled for several months during training.

Slovis said the filly was “drunk” and looked sedated on Aug. 23, and by the time she was admitted, she no longer had that “drunk” look. However, her neurologic signs were constantly changing. “I figured it was rabies, EEE (Eastern equine encephalitis), WEE (Western equine encephalitis), or West Nile virus,” said Slovis. He ran tests for all of the encephalitis viruses, and even took a spinal tap to rule out EPM.

“I wasn’t surprised it was WNV, but I’d never seen it before in a horse,” said Slovis after he received the positive report back from the national testing laboratory in Ames, Iowa. Slovis said the filly was in the clinic for three days, and each day her neurologic signs would change. First she was ataxic and had the “shakes” or muscle tremors in her neck, face, and thorax. Any movement caused the tremors to commence. Her depth perception was affected. “She’d go for her water bucket and miss by five inches,” he said