Mayo Clinic Care Network Content

Eastern equine encephalitis (EEE): What is it?

Eastern equine encephalitis (EEE) is a rare virus that's spread to people by mosquitoes that have been infected. You can't catch it from another person, and you can only get it from being bitten by an infected mosquito. The virus can cause swelling (inflammation) of your brain. The only way to lower your chance of getting EEE is to prevent mosquito bites.

Signs and symptoms don't usually start for four to 10 days and may include headache, fever, chills and vomiting. Signs and symptoms can worsen to disorientation, seizures and coma and lead to brain damage or, in some cases, death.

People who live in or travel to the woods or other outdoor areas may have a greater risk of getting EEE.

There aren't any effective treatments for eastern equine encephalitis. But you can lower your chance of getting EEE by preventing mosquito bites. You can prevent mosquito bites by:

  • Using insect repellent containing ingredients such as DEET or picaridin
  • Using permethrin to treat clothing
  • Wearing long pants and long-sleeved shirts when outside
  • Emptying standing water from outdoor containers
  • Having screens on windows and doors

Very few people are infected with EEE each year. By taking measures to prevent mosquito bites, you may be able to lower your risk of getting the virus.