A single horse at a stable in Wayne County, Michigan, has been confirmed to have tested positive for West Nile virus (WNV).
EDCC Health Watch is a marketing program by Equine Network that utilizes information from the Equine Disease Communication Center (EDCC) to generate and distribute verified equine disease reports. The EDCC is an independent nonprofit organization that relies on industry donations to provide accessible infectious disease information.
WNV 101
West Nile virus is transmitted to horses through bites from infected mosquitoes. While not all infected horses display symptoms, those that do may show:
- Flulike signs, such as mild anorexia and depression;
- Fine and coarse muscle and skin twitching;
- Hypersensitivity to touch and sound;
- Changes in mental activity;
- Occasional drowsiness;
- Propulsive walking;
- Spinal signs like weakness; and
- Ataxia, either asymmetrical or symmetrical.
There is no cure for West Nile virus in horses. However, some may recover with supportive care, though mortality rates can be as high as 30-40%.
Research has indicated that vaccines are effective in preventing WNV. Horses previously vaccinated should receive an annual booster, with some veterinarians recommending two boosters per year in areas with extended mosquito seasons. Unvaccinated horses will need a two-shot series within a three to six-week timeframe. It takes several weeks for full protection to develop after vaccination.
Alongside vaccinations, owners should take steps to reduce mosquito populations and limit exposure for their horses by:
- Eliminating stagnant water sources;
- Regularly cleaning and refilling water containers;
- Keeping animals indoors during peak mosquito activity times;
- Applying approved mosquito repellents for horses.