A recent report from the State Department of Agriculture revealed that an unvaccinated horse in Union County, Oregon, has tested positive for West Nile virus (WNV) on Aug. 11.
EDCC Health Watch, a program by Equine Network, uses information from the Equine Disease Communication Center (EDCC) to share verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations to provide accessible infectious disease information.
WNV 101
West Nile virus is transmitted to horses through mosquito bites. While not all infected horses show symptoms, those that do may experience:
- Flulike signs, such as mild anorexia and depression;
- Muscle and skin twitching;
- Hypersensitivity to touch and sound;
- Mental changes, like appearing daydreamy or disoriented;
- Occasional drowsiness;
- Propulsive walking without control;
- Spinal weakness or ataxia.
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 prevention method, with annual booster shots recommended for previously vaccinated horses and a two-shot series for unvaccinated horses.
In addition to vaccination, owners can reduce the risk of WNV by eliminating stagnant water sources, maintaining clean water containers, keeping horses indoors during peak mosquito times, and using approved mosquito repellents for horses.