Kentucky Horse Tests Positive for WNV

A 6-year-old Standardbred mare from Fleming County, Kentucky, tested positive for West Nile virus today (Sept. 2), according to a report from E.S. "Rusty" Ford, equine programs manager for the Office of the State Veterinarian.

The mare reportedly began displaying rear limb ataxia (incoordination) on Aug. 26. The signs progressed to forelimb ataxia and changes in mentation (mentality) before tests carried out at the University of Kentucky Veterinary Diagnostic Laboratory confirmed she was WNV-positive earlier today, the report said.

The affected horse, who is recovering at a veterinary clinic, has no prior WNV vaccination history.

This is Kentucky's first confirmed case of WNV this year. Cases have already been confirmed in Georgia, California, Nevada, and Texas in 2011.

In 2010 the USDA's National Animal Health Surveillance System reported 125 confirmed WNV cases in 28 states. Clinical signs for WNV include flulike conditions where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations (twitching); hyperesthesia, or 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 (incoordination on one or both sides, respectively). Equine mortality rate can be as high as 30-40%.

The American Association of Equine Practitioners recommends vaccinating all horses against WNV as a preventive measure. In addition to vaccination, minimize mosquito populations by eliminating breeding and resting areas and keeping mosquitoes away from horses. For example, reduce or eliminate sources of stagnant or standing water in close proximity to horses, remove manure from areas near the horses, keep horses stalled during peak mosquito periods (i.e., dawn and dusk), use equine-approved mosquito repellents or protective fly gear (i.e., fly masks or sheets), and place fans in barns or stalls to maintain air movement, as mosquitoes don't fly well in wind.

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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