Florida Horse Positive for West Nile Virus
A 26-year-old, unvaccinated Quarter Horse gelding in Hernando County, Florida, has tested positive for West Nile virus.
A 26-year-old, unvaccinated Quarter Horse gelding in Hernando County, Florida, has tested positive for West Nile virus. | Wikimedia Commons

A 26-year-old Quarter Horse gelding in Hernando County, Florida, tested positive for West Nile virus on January 20. The horse, who is unvaccinated, developed clinical signs on January 6, including listlessness, fever and inappetence. He is currently affected and alive.

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

WNV 101

West Nile virus is transmitted to horses via bites from infected mosquitoes. Not all infected horses show clinical signs, but those that do can exhibit:

  • Flulike signs, where the horse seems mildly anorexic and depressed;
  • Fine and coarse muscle and skin fasciculation (involuntary twitching);
  • Hyperesthesia (hypersensitivity to touch and sound);
  • Changes in mentation (mental activity), when horses look like they’re daydreaming or “just not with it”;
  • Occasional drowsiness;
  • Propulsive walking (driving or pushing forward, often without control); and
  • Spinal signs, including asymmetrical weakness; and
  • Asymmetrical or symmetrical ataxia.

West Nile virus has no cure. However, some horses can recover with supportive care. Equine mortality rates can reach 30-40%.

Studies have shown that vaccines can be effective WNV prevention tools. Horses vaccinated in past years need an annual booster shot, but veterinarians might recommend two boosters annually—one in the spring and another in the fall—in areas with prolonged mosquito seasons. In contrast, previously unvaccinated horses require a two-shot vaccination series in a three- to six-week period. It takes several weeks for horses to develop protection against the disease following complete vaccination or booster administration.

In addition to vaccinations, owners should work to reduce mosquito population and breeding areas and limit horses’ mosquito exposure by:

  • Removing stagnant water sources;
  • Dumping, cleaning, and refilling water buckets and troughs regularly;
  • Keeping animals inside during insect feeding times (typically early in the morning and evening); and
  • Applying mosquito repellents approved for equine use.
Brought to you by Boehringer Ingelheim, The Art of the Horse

Share
Related Articles
EDCC-rsz-12
Michigan Yearling Tests Positive for Strangles
EDCC-3-Larger-Logo-scaled
Equine Network, Boehringer Ingelheim Launch EDCC Health Watch Text Alerts
EDCC-rsz-14-scaled
Strangles Case Confirmed at Florida Boarding Facility
EDCC-rsz-19
Ontario Mare Tests Positive for Influenza
Newsletter
Receive news and promotions for Horse & Rider and other Equine Network offers.

"*" indicates required fields

Name*
Country*

Additional Offers

Additional Offers
This field is for validation purposes and should be left unchanged.