Kentucky Equine West Nile Case Tally Rises to Seven

Two more cases of West Nile virus (WNV) were confirmed in Kentucky horses yesterday (Aug. 23), bringing the total for 2012 to seven, according to a statement from Equine Programs Manager E.S. "Rusty" Ford.

Two Henry County horses--a 6-year-old Palomino gelding and a 3-year-old Quarter Horse gelding--tested positive for the disease after developing clinical signs on Aug. 17 and Aug. 19, respectively. Ford said that the horses, who reside on different properties, do not have any WNV vaccination history.

The Palomino presented with mild ataxia (incoordination), primarily in the rear limbs. The Quarter horse presented with moderate ataxia, lethargy, and proprioceptive deficits (lack of physical awareness of limbs and their placement). As of Aug. 23, both horses were alive and reportedly recovering.

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 asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia. Equine mortality rate can be as high as 30-40%.

The USDA Animal and Plant Health Inspection Service reported 87 cases of WNV in U.S. horses in 2011; only one case was reported that 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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