Kentucky animal health officials have confirmed an additional case of equine West Nile virus (WNV) in 2012, according to a Sept. 19 statement from Kentucky Equine Programs Manager E.S. "Rusty" Ford.

The affected horse–an unvaccinated 5-year-old Tennessee Walking Horse gelding from Garrad County–began showing clinical signs on Sept. 17. He presented muscular fasciculation, abdominal discomfort, and neurologic deficits (specifically knuckling over while walking) that progressively worsened, Ford’s statement said. He was euthanized on Sept. 18.

Kentucky has now confirmed 12 WNV cases on 11 premises in 10 counties (Bourbon, Franklin, Garrad, Henderson, Henry, Laurel, Metcalfe, Scott, Shelby, and Warren) so far this year. Six are recovering while six, including the Garrad County gelding, have been euthanized. Ford reported that eight affected horses were unvaccinated, three were partially vaccinated, and one was reportedly vaccinated.

The United States Geological Survey Disease Maps, updated Sept. 18, report 299 cases of equine WNV in the United States thus far in 2012.

Clinical signs for WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations (twitching); 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 asymme