EASTERN EQUINE ENCEPHALITIS IS A RARE MOSQUITO-BORNE VIRAL DISEASE THAT CAN ONLY BE TRANSMITTED TO PEOPLE BY THE BITE OF AN INFECTED MOSQUITO. EASTERN EQUINE ENCEPHALITIS IS REGARDED AS ONE OF THE MOST DEADLY MOSQUITO-BORNE DISEASES IN THE UNITED STATES. SYMPTOMS INCLUDE HIGH FEVER, STIFF NECK, HEADACHE, AND LACK OF ENERGY.

view Eastern equine encephalitis fact sheet (MDPH)

Massachusetts has the second largest number of reported human cases of eastern equine encephalitis in the country. Between 1964 and 2005, 242 people in the U.S. were infected with the EEE virus. Of these people, 12% resided in Massachusetts.

Outbreaks of eastern equine encephalitis occur in Massachusetts about every 10 to 20 years. An outbreak typically lasts two to three years. The most recent outbreak of EEE in Massachusetts began in 2004 and included 13 cases with six fatalities through 2006. During this period, infected mosquitoes were detected in Plymouth, Bristol, Middlesex, Worcester, Norfolk, and Essex counties.

The EEE virus is carried by birds that live in natural wetlands, and it is usually found only in birds and mosquitoes that do not bite people. However, in years when the virus infects large number of birds, it may infect other species of mosquitoes that do bite horses and people.

To protect yourself from eastern equine encephalitis and other mosquito-borne diseases, see the health department's prevention tips.

For more information, visit the Massachusetts Department of Public Health arbovirus website.