The Utah Department of Agriculture has reported that two horses in the state have tested positive for West Nile virus (WNV).
In Weber County, a 4-year-old gelding that was not vaccinated tested positive on July 21 after showing clinical signs on July 17. Fortunately, he has since recovered.
In Box Elder County, another horse has also tested positive for WNV, although further details are currently unavailable.
EDCC Health Watch is an Equine Network 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 is supported by industry donations in order to provide open access to infectious disease information.
WNV 101
West Nile virus is transmitted to horses through bites from infected mosquitoes. While not all infected horses display clinical signs, those that do may exhibit symptoms such as:
- Flulike signs, including mild anorexia and depression;
- Fine and coarse muscle and skin twitching;
- Hypersensitivity to touch and sound;
- Changes in mental activity;
- Occasional drowsiness;
- Propulsive walking without control;
- Spinal signs like weakness; and
- Ataxia (lack of coordination).
There is no cure for West Nile virus in horses, but supportive care can help some recover. Mortality rates in equines can reach 30-40%.
Research indicates that vaccines are effective in preventing WNV. Horses previously vaccinated should receive an annual booster shot, while unvaccinated horses may require a two-shot series over a few weeks. It takes time for horses to develop immunity after vaccination.
Aside from vaccinations, owners can reduce mosquito exposure for their horses by eliminating breeding areas, regularly cleaning water sources, keeping animals indoors during peak mosquito times, and using approved mosquito repellents for horses.