The Kentucky State Veterinarian’s office announced Sept. 17 that a Bourbon County horse has tested positive for West Nile virus (WNV), the fourth confirmed case in the commonwealth this year.

In a statement Kentucky Equine Programs manager E.S. "Rusty" Ford relayed that the yearling Thoroughbred colt with no WNV vaccination history presented with a fever on Sept. 9. By the next day, he exhibited a fever of 101.8$deg;F in addition to shoulder and neck muscle fasciculations (twitching). As of Sept. 17, the attending veterinarian reported that the colt is responding to treatment and is showing improvement, Ford’s statement said.

In 2014 Kentucky confirmed four cases of WNV in horses on four premises.

West Nile is transmitted to horses via bites from infected mosquitoes. Clinical signs for WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations; 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%