The mosquito-borne virus, though rare, is severe, with a mortality rate of about 30 percent and many survivors experiencing ongoing neurological issues.
A rare but dangerous mosquito-transmitted disease has prompted heightened vigilance in nearly a dozen Massachusetts communities. Some towns have responded by closing parks after dark, restricting outdoor activities, and rescheduling public events.
This month, Massachusetts health officials confirmed the state’s first human case of Eastern Equine Encephalitis (EEE) for the year. The case involved an elderly man from Worcester County, west of Boston. As of Saturday, ten communities are classified as high or critical risk for the virus. In response, Plymouth, located about 40 miles south of Boston, has closed all public parks and fields from dusk until dawn when mosquitoes are most active. Nearby, Oxford has banned outdoor activities on town property after 6 p.m.
The outbreak coincides with an extended mosquito season across the United States, driven by rising global temperatures and increased humidity. The Northeast, in particular, has experienced a significant increase in mosquito days—defined as days with average humidity of at least 42 percent and temperatures between 50 and 95 degrees. In Massachusetts, there has been an average of 14 additional mosquito days compared to the period from 1980 to 2009. Scientists warn that longer mosquito seasons could elevate the risk of other mosquito-borne diseases like dengue and malaria.
Massachusetts health officials will conduct mosquito spraying between dusk and dawn throughout this week in Plymouth and Worcester counties to curb the spread of EEE.
“Aerial spraying will focus on mosquitoes carrying the EEE virus. While these measures are critical to reducing transmission risk, it is essential for everyone to stay alert and follow personal protection guidelines to keep our community safe,” said Ashley Randle, Commissioner of the Massachusetts Department of Agricultural Resources.
Residents are advised to use mosquito repellents, eliminate standing water around their homes, wear protective clothing, and adjust outdoor activities to avoid peak mosquito activity times. Symptoms of EEE include fever, headache, vomiting, diarrhea, seizures, behavioral changes, and drowsiness. There are no vaccines or specific treatments available for Eastern Equine Encephalitis.