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Neurologic Disease in Horse

Mosquito-borne diseases in horses: these diseases are transmitted from a mosquito to a horse. they are not transmitted from horse to horse. Humans can be infected with these diseases.

Eastern/Western Equine Encephalitis/West Nile Virus

Eastern and Western Equine Encephalitis and West Nile Viruses are viral infections that attack the brain and spinal cord in horses and humans. Mosquitoes spread these viruses and when they occur are almost always fatal within 48-72 hours.

In 2010 Michigan had an outbreak with more than 120 horses with symptoms associated with the Eastern Equine Encephalitis virus and 57 confirmed cases. Four human cases of Eastern Equine Encephalitis also occurred in southern Michigan during the equine outbreak. The mosquitoes, which caused these outbreaks, will move north in the state this year. The good news? These two diseases are preventable!!


West Nile Virus

We have seen several cases of confirmed West Nile Virus in Horses in our area in the last three years. Some horses can survive West Nile Virus infection but they rarely return to their pre infected level of function. It’s a devestating disease which can be prevented.


Vaccinate, Vaccinate, Vaccinate!! The newer vaccines provide very effective Protection!

Take Measures to reduce mosquito exposure:

  • Eliminate mosquito breeding areas: standing or stagnate water,
  • Use mosquito repellents on yourself and your horse: sprays, sheets, etc.
  • Use screens on barn doors and windows
  • Use circulating fans inside the barn: this makes it hard for mosquitoes to fly in and bite

Signs in horses of Eastern Equine Encephalitis

  • Fever
  • Severe Depression
  • Erratic Behavior
  • Weakness or Lack of Coordination
  • Head Pressing
  • Muscle twitching or tremors
  • Difficulty Chewing or swallowing
  • Difficulty Walking

Unfortunately there is no cure for this deadly disease. Early recognition and intervention is key. Please, protect your horse by vaccinating him. If your horse has any of the above signs, call your veterinarian right away.