According to the State Animal Health Official, a single horse in Uinta County, Wyoming, has been confirmed to have tested positive for West Nile virus (WNV).
The Equine Network’s EDCC Health Watch is a marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that relies on industry donations to provide open access to infectious disease information.
WNV is transmitted to horses through mosquito bites. Symptoms in infected horses can vary and may include flulike signs, muscle twitching, hypersensitivity, changes in mentation, drowsiness, propulsive walking, and spinal signs. There is no cure for West Nile virus, and mortality rates in horses can be as high as 30-40%.
Vaccination has been shown to be an effective tool in preventing WNV. Horses should receive annual booster shots, with some veterinarians recommending two boosters annually in areas with prolonged mosquito seasons. Unvaccinated horses will require a two-shot vaccination series over a three to six-week period.
In addition to vaccination, owners should take steps to reduce mosquito populations and limit their horses’ exposure to mosquitoes by removing stagnant water sources, regularly cleaning and refilling water buckets and troughs, keeping animals indoors during peak insect feeding times, and using approved mosquito repellents for equine use.

