About Eastern Equine Encephalitis

Key Points

  • Eastern equine encephalitis is caused by a virus spread to people through the bite of an infected mosquito.
  • It is a rare but serious disease.
  • People living in areas where eastern equine encephalitis virus circulates should protect themselves by preventing mosquito bites.
Culiseta melanura mosquito on a feather


Eastern equine encephalitis virus is spread to people by the bite of an infected mosquito.

Only a few cases are reported in the United States each year. Most cases occur in eastern or Gulf Coast states.

Although rare, eastern equine encephalitis is very serious. Approximately 30% of people with eastern equine encephalitis die, and many survivors have ongoing neurologic problems. Symptoms of eastern equine encephalitis can include fever, headache, vomiting, diarrhea, seizures, behavioral changes, and drowsiness.

There are no vaccines to prevent or medicines to treat eastern equine encephalitis.

You can reduce your risk of infection with eastern equine encephalitis virus by preventing mosquito bites.