Find My Horses Presents: West Nile, EEE Detected in Tennessee Horses
- Nov 8, 2016
- Original Article Link
With unseasonably warm weather persisting well into the fall, mosquito-borne illnesses remain a serious health threat for Tennessee horses.
A horse in Dyer County and a horse in Gibson County both recently tested positive for West Nile virus (WNV). Additionally, a horse in Chester County has tested positive for Eastern equine encephalitis (EEE).
Both WNV and EEE are viral diseases transmitted to horses by infected mosquitoes.
“We typically think of mosquitoes as a summer-time pest,” said Tennessee State Veterinarian Charles Hatcher, DVM. “However, the record heat this fall has allowed mosquitoes to endure. It’s critical that livestock are current on annual vaccinations for year-round protection.”
Vaccines have proven to be a very effective prevention tool for both WNV and EEE. 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.
Clinical signs for WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations; 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%.
Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care. Horses that survive might have long-lasting impairments and neurologic problems.
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