California Confirms First Equine WNV Case of 2017

California Confirms First Equine WNV Case of 2017

West Nile is transmitted to horses via bites from infected mosquitoes.

Photo: Photos.com

The California Department of Food and Agriculture (CDFA) reported July 13 the state’s first confirmed equine West Nile virus (WNV) case of 2017.

“On July 13, 2017, a 14-month-old Quarter Horse filly in Kern County, displaying severe neurologic signs, was confirmed positive for West Nile virus (WNV),” the agency said in a statement. “Due to the severity of signs, the filly was euthanized.

“CDFA continually monitors and investigates equine neurologic cases for the presence of WNV in California,” the statement continued. “CDFA urges horse owners to consult their veterinarian concerning a WNV vaccination program to ensure maximum protection of their horses.”

West Nile is transmitted to horses via bites from infected mosquitoes. Clinical signs for 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 rate can be as high as 30-40%.

Health Alert: West Nile Virus

Horse owners should also consult their private practicing veterinarian to determine an appropriate disease prevention plan for their horses. Vaccines have proven to be a very effective prevention tool. Horses that have been vaccinated in past years will need an annual booster shot. However, if an owner did not vaccinate their animal in previous years, the horse will need the two-shot vaccination series within a three- to six-week period.

In addition to vaccinations, horse owners also need to reduce the mosquito populations and their possible breeding areas. Recommendations include removing stagnant water sources, keeping animals inside during the bugs’ feeding times, which are typically early in the morning and evening, and using mosquito repellents.

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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