How to Know If a Horse Has West Nile Virus

The West Nile virus causes disease in horses, birds and people. The brain and spinal cord may become infected. The disease was found only in Africa, Asia and southern Europe until 1999, when it spread to the United States. The virus is spread by mosquitoes. According to the University of Nebraska's West Nile Guide for Horse Owners, it can take up to 15 days after the infection for symptoms to appear. As of 2010, there is no treatment for West Nile virus other than supportive veterinary care. It has a 30 to 40 percent mortality rate, according to data collected by the University of Nebraska. West Nile can be prevented if you limit your horse's exposure to mosquitoes and vaccinate it.

Things You'll Need

  • Horse thermometer
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Instructions

    • 1

      Observe your horse for muscle tremors or an altered gait. These are the most common symptoms of West Nile virus. These symptoms are caused by the infection in the spinal cord, which affects certain nerve endings.

    • 2

      Take your horse's temperature. Horses with West Nile virus may have fever 10 days before other symptoms of the infection appear. If you live in a humid area populated by mosquitoes, take your horse's temperature regularly to monitor any sudden changes.

    • 3

      Watch for other symptoms which include a loss of appetite, depression, weakness of the hind legs, aimless wandering, difficulty or inability to swallow, partial paralysis and impaired vision. These symptoms are very similar to the symptoms of the rabies virus, equine protozoal myelitis, equine encephalitis and other neurological diseases. If your horse has any of these symptoms, contact your veterinarian immediately.