Tips for Preventing West Nile Virus in Horses

Tips for Preventing West Nile Virus in Horses

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What is West Nile Virus?

West Nile Virus is a potentially deadly disease. It causes an inflammation of the brain called encephalomyelitis and up to 40% of infected horses can die. First detected in 1999, West Nile Virus has become increasingly widespread in the United States.

How is West Nile Virus Spread?

Birds are the main carriers of West Nile Virus, but the virus is spread by mosquitoes. Horses and humans become infected after being bitten by a mosquito that has fed on the blood of an infected bird. When the virus enters a horse’s bloodstream, it spreads to the spinal cord and the brain and causes inflammation.

Signs and Symptoms

West Nile Virus symptoms in horses typically manifest within 3–15 days of exposure and include fever, stumbling, depression, inability to rise, teeth grinding, inability to swallow, muscle tremors, paralysis of the lower lip, excessive sweating, head pressing, convulsions, and in extreme cases, coma.

If you suspect your horse is infected with the virus, contact your veterinarian immediately.


Deterring mosquitoes is the best way to minimize a horse’s chances of becoming infected with West Nile Virus. Here are a few helpful hints:

1.     Protect your horse.

Mosquitoes are most active from dusk to dawn. When possible, keep your horse stabled during this time period or keep your horse in a fly mask, fly sheet and fly boots. While not a guaranteed solution, horsewear can help add some protection for your horse.

Farnam Centaura is effective against mosquitoes that carry West Nile Virus

Apply repellent and sprays to help keep mosquitoes away from your horse. Repellent containing Permethrin, Picaridin, or DEET, like Farnam® Centaura™, can be very helpful in repelling mosquitoes from your horse. 

2.     Keep mosquitoes out of barns and stalls.

Mosquitoes like to come indoors. Do your best to keep screens on the doors and windows of your barn or stable.

Placing fans inside a barn or stall helps increase air flow and mosquitoes don’t fly well in the wind. Avoid placing incandescent bulbs inside your barn as mosquitoes will flock to them.

3.     Eliminate mosquito breeding grounds.

Mosquitoes tend to lay their eggs in standing water. Eliminate the number of stagnant pools of water around your barn or stable. Be sure to empty and clean water troughs and buckets often.

West Nile Virus can be a serious threat to your horse. Be sure to check your local news often to stay up-to-date on the latest developments in your area. has the pest control products to help keep your horse safe!  Shop Pest Control

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  • Published:
  • Updated: 7/29/2019: 9:13:03 PM ET
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