Eastern equine encephalitis (EEE) is a mosquito-borne disease that is becoming more common in several US states, most notably in Massachusetts where 12 individuals contracted the disease during 2019. Every year in the US, an average of 11 people contract EEE from mosquito bites, and the states with the highest number of annual cases include Massachusetts, New York, Georgia, Florida, and Michigan. While EEE cases in Massachusetts will likely fall short of last year’s numbers, three cases have already been reported in the state this year.

A Plymouth County boy below the age of 18 was the first reported EEE victim in Massachusetts this year, but information concerning the boy’s medical condition has not been released. In response to the boy’s diagnoses last July, state officials raised the mosquito-borne disease risk to “critical” in the victim’s hometown of Middleborough. Residents living in cities and towns deemed to be at critical risk for mosquito-borne disease transmission are prohibited from setting foot on city-owned property between dusk and dawn when disease-carrying mosquitoes are active.

On August 14th, a 60 year old Hampton County woman became the second individual to contract EEE in Massachusetts, and five days later, a 90 year old Plymouth County man became the third, and so far, the last reported individual to contract EEE in Massachusetts. In addition to EEE, mosquitoes have transmitted the West Nile virus (WNV) to three individuals in Massachusetts this year. All three WNV cases were reported during August, the first of which was likely contracted in either Essex or Middlesex Counties. Last year, five WNV cases were reported in Massachusetts, but the disease is not considered a major public health threat in the state. In Massachusetts, WNV-carrying mosquitoes are most active in Boston and neighboring cities and towns, but mosquitoes can transmit the disease throughout the state.

Have you been taking measures to prevent mosquito bites this summer?