Kentucky Confirms Sixth Equine WNV Case of 2017

Kentucky Confirms Sixth Equine WNV Case of 2017

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


The Kentucky State Veterinarian's office has announced that a horse from Metcalfe County has tested positive for West Nile virus (WNV). This is the sixth equine WNV case confirmed in the commonwealth this year.

In a Sept. 9 statement Kentucky Equine Programs manager E.S. "Rusty" Ford said the case was confirmed Sept 8.

Ford said the 13-year-old Tennessee Walking Horse gelding began exhibiting signs of disease on Sept. 2, including a head tilt, front-limb proprioceptive (a horse's awareness of where his feet are) deficits, and some ataxia (incoordination). On Sept. 8, the attending veterinarian said the horse was stable with some motor improvement noted. The horse has no WNV vaccination history, Ford said.

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; in areas with a prolonged mosquito season, veterinarians might recommend two boosters annually—one in the spring and another in the fall. 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 (typically early in the morning and evening), using fans to disrupt mosquitoes’ flight patterns, and applying mosquito repellents approved for equine use.

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.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More