Due to the rise in temperatures and mosquito populations, Utah horse owners are being advised to vaccinate their animals to protect them from the West Nile virus (WNV).

“WNV is a reportable disease and is part of our statewide information and alert system designed to protect animal and human health,” said State Veterinarian Barry Pittman, DVM. “Our Animal Health Program is part of a regional and national notification system designed to prevent the spread of diseases that affect livestock and the human population. Any equine with WNV would be prevented from traveling across state lines.”

Mosquito monitoring for WNV continues throughout the state and is ongoing throughout peak months. To date, no human or animal WNV cases have been reported.

Laboratory test results confirm the presence of WNV mosquitoes in the Vernal, Utah, area. A monitoring and collection system designed to detect the presence of WNV mosquitoes reported two positive findings in the Uintah Basin district.

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 (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 3