Eastern equine encephalitis (EEE) is a rare but serious disease caused by a virus.
The virus that causes EEE is spread through the bite of an infected mosquito. In Massachusetts, the virus is most often identified in mosquitoes found in and around freshwater, hardwood swamps. More information about different types of mosquitoes that can spread the virus can be found on the MDPH website at www.mass.gov/dph/mosquito.
EEE virus particularly infects birds, often with no evidence of illness in the bird. Mosquitoes become infected when they bite infected birds. Although humans and several other types of mammals, particularly horses and llamas, can become infected, they do not spread disease.
- EEE Fact Sheet (English)
- EEE Fact Sheet (Portuguese)
- West Nile Fact Sheet (English)
- West Nile Fact Sheet (Portuguese)