Eastern Equine Encephalitis (EEE)


Eastern Equine Encephalitis (EEE) is a mosquito borne viral disease that can present as a generalized infection or as a brain infection.

Following a bite by an infected mosquito, there is an incubation period of four to 10 days. Symptoms of a generalized infection have a sudden onset characterized by chills, fever, lack of energy, joint and muscle pains. These symptoms usually last one to two weeks and the person recovers completely. Symptoms of a brain infection (encephalitis) include fever, headache, restlessness, drowsiness, loss of appetite, vomiting, diarrhea, and may progress to convulsions and coma. Encephalitis may be fatal.

There is no curative treatment for EEE. Care is focused on supportive treatment which may involve  hospitalization especially for those with encephalitis.

Mosquito testing is routinely carried out by the Massachusetts Department of Public Health from May to October. 

Prevention of EEE involves reducing your chances of getting bitten by a mosquito.

  • Be aware of mosquito peak hours - Plan outdoor activities to avoid the hours between dusk and dawn, when mosquitoes are most active.
  • Clothing can help reduce mosquito bites - When you are outdoors, wear long pants, a long-sleeved shirt and socks. This may be difficult to do when the weather is hot, but it will help keep mosquitoes away from your skin.
  • Apply insect repellent when outdoors - Use insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus on exposed skin and/or clothing. The repellent/insecticide permethrin can be used on clothing to protect through several washes. Always follow the directions on the package.

For more information and updates, please refer to: