Oregon, Kentucky Report New Equine WNV Cases

Oregon, Kentucky Report New Equine WNV Cases

WNV is a viral disease transmitted to horses by infected mosquitoes.

Photo: Photos.com

Animal health officials in Oregon have confirmed the state's third equine case of West Nile virus (WNV) for 2013, while officials say a fifth Kentucky horse has tested positive for the virus.

Officials reported Oct. 2 that a horse located north of Hermiston in Umatilla County, Ore., had tested positive for the virus on Sept. 27. Testing was carried out at the Oregon State University Veterinary Diagnostic Lab in Corvallis. This is the first confirmed equine case in Umatilla County since 2009, a press release said, and the horse tested positive five weeks after officials first detected the virus in mosquitoes in Umatilla County.

According to an Oregon Health Authority Public Health Department surveillance map, one horse in Malheur County and another in Union County have already tested positive for WNV this year. In 2012, Oregon reported two equine WNV cases.

Meanwhile, the Kentucky State Veterinarian's office announced Oct. 2 that a Calloway County horse has tested positive for WNV.

A statement from Kentucky Equine Programs manager E.S. "Rusty" Ford indicated that an unvaccinated, 14-year-old Quarter Horse mare began showing signs of disease on Sept. 25. As of Oct. 2, the mare was reportedly showing improvement, Ford said.

This is the fifth equine WNV case confirmed this year in the commonwealth. Cases have now been confirmed in Calloway, Christian, Edmonson, Hopkins, and Todd counties. All of the WNV-affected horses in Kentucky—none of which were vaccinated against the disease—are reportedly recovering. Thirteen WNV cases were reported last year in Kentucky horses.

WNV is a viral disease transmitted to horses by infected mosquitoes. 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 (incoordination). Equine mortality rate can be as high as 30-40%.

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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