Recent cases of equine West Nile virus (WNV) have been reported by the Equine Disease Communication Center:
- Weld County, Colorado: A vaccinated yearling Paint filly tested positive on Sept. 1 after showing neurologic signs on Aug. 31. The horse deteriorated quickly and had to be euthanized.
- Weber County, Utah: One horse tested positive.
- Duchesne County, Utah: Two horses tested positive.
EDCC Health Watch is a marketing program by Equine Network that uses information from the Equine Disease Communication Center (EDCC) to create and distribute verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations to provide accessible infectious disease information.
WNV 101
Horses can contract West Nile virus through bites from infected mosquitoes. Clinical signs may include:
- Flulike symptoms such as mild anorexia and depression;
- Muscle twitching;
- Hypersensitivity to touch and sound;
- Changes in mental activity;
- Drowsiness;
- Propulsive walking;
- Spinal signs like weakness and ataxia.
There is no cure for West Nile virus in horses, and mortality rates can be high. Vaccination is the best prevention method, with annual boosters recommended for previously vaccinated horses. Unvaccinated horses require a two-shot series over a few weeks to build immunity.
Apart from vaccination, owners should take steps to reduce mosquito populations and protect horses from bites by eliminating stagnant water sources, cleaning water containers regularly, keeping horses indoors during peak mosquito activity times, and using approved mosquito repellents.