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%