First Case of West Nile in Wyoming Horse This Year Puts Owners on Alert

A horse in Johnson County has tested positive for West Nile virus, making it Wyoming’s first confirmed equine case of the season, according to the state vet’s office, the Horse reports.

The news came through EDCC Health Watch, which tracks and shares verified animal disease alerts. It’s a reminder that mosquito season is no joke — and that horse owners should be stepping up their prevention game right now.

West Nile virus (WNV) spreads through mosquito bites, and while not every infected horse shows symptoms, the ones that do can get seriously sick. We’re talking about:

• Flu-like behavior — tired, depressed, not eating
• Muscle twitching and weird skin shivers
• Hypersensitivity to sound and touch
• Mental fog — like the horse is zoned out
• Wobbliness and weird walking patterns
• Weakness in the limbs, sometimes lopsided

There’s no cure for West Nile once it hits — just supportive care. And the bad news? Mortality rates can reach up to 40% in horses that show symptoms.

Vaccinate, vaccinate, vaccinate.
Most vets recommend a spring booster, and in mosquito-heavy areas, a fall booster too. If your horse hasn’t been vaccinated before, it needs a two-shot series over 3–6 weeks — and it takes a few weeks after that to build immunity, so the sooner the better.

Beyond vaccines, horse owners should do all they can to make life tough for mosquitoes. That includes:

• Dumping standing water (breeding heaven for mozzies)
• Scrubbing water troughs and buckets regularly
• Keeping horses indoors during peak mosquito hours (early morning & evening)
• Using mosquito repellents made for horses

As summer stretches on, vets warn that more cases could pop up — especially if mosquito populations stay high.