Fourth case of dangerous mosquito-borne virus confirmed in Massachusetts

Fourth Case of Eastern Equine Encephalitis (EEE) Confirmed in Massachusetts

Massachusetts health officials have confirmed a fourth case of the dangerous mosquito-borne illness, Eastern equine encephalitis (EEE), on Monday. The patient, a man in his 50s, resides in Middlesex County, an area classified as high-risk for EEE, according to the Massachusetts Department of Public Health (DPH).

In 2024, EEE cases have surfaced across at least five states, including Vermont, Wisconsin, New Jersey, Massachusetts, and New Hampshire. EEE is a rare but serious disease transmitted to humans through the bite of an infected mosquito.

“This year’s EEE season has been unusually active, raising significant concerns among Massachusetts communities,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “While the disease remains uncommon, the risk is higher in several regions.”

Goldstein urged residents to take extra precautions, especially with the forecast predicting warm, sunny weather. He recommended rescheduling outdoor activities that take place during peak mosquito hours, from dusk to dawn, in high-risk areas.

So far this year, Massachusetts has recorded 91 mosquito samples testing positive for EEE. The last significant outbreak in the state occurred in 2019-2020, resulting in 17 human cases and seven fatalities. In addition to the four human cases this year, two horses in Massachusetts have also tested positive for EEE.