Two Montana Horses Positive for WNV
- Topics: Article, Vaccinations, West Nile Virus (WNV)
Test results returned Tuesday (Aug. 21) have confirmed that two Montana horses were infected with West Nile virus (WNV) before their deaths, Steve Merritt, public information officer for the Montana Department of Livestock, confirmed today (Aug. 23).
Merritt said both horses displayed "typical clinical signs," including neurologic deficits, hind quarter paralysis, and eventual recumbency. Both animals were euthanized, he said. Neither horse was vaccinated against the disease, he added.
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%.
The USDA Animal and Plant Health Inspection Service reported 87 cases of WNV in U.S. horses in 2011; none of those cases were confirmed in Montana
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