Kentucky Reports New Equine WNV Case

Kentucky Reports New Equine WNV Case

Studies have shown that the WNV vaccine has a substantial effect on preventing disease.

Photo: Anne M. Eberhardt/The Horse

Although snow has already fallen in some parts of the commonwealth, Kentucky animal health officials reported a new equine West Nile virus (WNV) case yesterday (Nov. 13).

According to a statement from Kentucky Equine Programs manager E.S. "Rusty" Ford, the affected 10-year-old unvaccinated Quarter Horse gelding residing in Christian County presented Nov. 8 with mild rear-limb ataxia (incoordination). As of Nov. 13, the horse's condition was reportedly improving.

Thus far in 2013, 12 Kentucky horses have tested positive for WNV in 10 counties: Calloway, Christian (2), Edmonson, Graves (2), Hopkins, Lincoln, Todd, Trigg, Union, and Warren. Two affected horses were euthanized, but the remaining horses are recovering or have recovered.

WNV is a viral disease transmitted to horses by infected mosquitoes. Clinical signs of WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculation; hyperesthesia (hypersensitivity to touch and sound); changes in mentation (mentality), when horses look like they are daydreaming or "just not with it"; occasional somnolence (drowsiness); propulsive walking (driving or pushing forward, often without control); and "spinal" signs, including asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia. Equine mortality rates can be as high as 30-40%.

Studies have shown that the WNV vaccine has a substantial effect on preventing disease. The American Association of Equine Practitioners recommends vaccinating all foals and horses against WNV. For horses residing in the northern United States veterinarians recommend vaccinating in the spring prior to peak mosquito levels. In the south, where mosquito populations are present year-round, horses might be vaccinated more frequently. In addition to geography, age and exposure play an important role in deciding how often to vaccinate horses.

The United States Department of Agriculture Animal and Plant Health Inspection Service reported 627 cases of WNV in U.S. horses in 2012; 13 cases were reported last year in Kentucky.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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