Three new cases of equine West Nile virus (WNV) have been reported to the Equine Disease Communication Center, with cases in California and Kansas.
In California, a 5-year-old Quarter Horse mare in Fresno County tested positive for WNV on Aug. 14. The mare, who was under-vaccinated, showed symptoms of ataxia and muscle fasciculations on Aug. 3. Fortunately, she is alive and recovering.
Two additional cases have been confirmed in Kansas, one in Rawlins County and the other in Jewell County. The current condition of these horses is unknown.
EDCC Health Watch is a marketing program by Equine Network that uses information from the Equine Disease Communication Center (EDCC) to create and share verified equine disease reports. The EDCC is an independent nonprofit organization funded by industry donations to provide accessible information on infectious diseases.
WNV 101
West Nile virus is transmitted to horses through bites from infected mosquitoes. Clinical signs in infected horses may include:
- Flulike symptoms such as mild anorexia and depression;
- Muscle and skin fasciculations;
- Hypersensitivity to touch and sound;
- Changes in mental activity;
- Propulsive walking;
- Spinal signs like weakness and ataxia.
There is no cure for West Nile virus in horses, and mortality rates can range from 30-40%. Vaccination is a key prevention method, with annual boosters recommended for previously vaccinated horses and a two-shot series for unvaccinated horses.
In addition to vaccinations, owners can reduce the risk of WNV by eliminating stagnant water sources, regularly cleaning water containers, keeping horses indoors during peak mosquito activity times, and using approved mosquito repellents.