Officials raise EEE risk levels in 11 Mass. towns


The rare but serious disease was detected in mosquitos this week in Sutton and Southbridge.

Mosquitoes infect humans with the virus that causes EEE after getting it from birds. Rick Bowmer/AP

New instances of eastern equine encephalitis (EEE) were detected in Massachusetts recently, raising official risk levels in 11 towns.

The rare but serious disease was found in mosquito samples collected on Sept. 11 in Sutton and Southbridge, the Massachusetts Department of Public Health said. Due to these findings, the risk level was raised to “high” in Dudley, Douglas, Oxford, Southbridge, Sutton, and Webster. It was raised to “moderate” in Auburn, Charlton, Grafton, Millbury, and Northbridge.

Officials announced that the first EEE-positive mosquitos of 2023 were found in Douglas and Southbridge on Sept. 1. No human or other animal has tested positive for the disease in Massachusetts yet this year, but it has been found in a donkey in Rhode Island. Mosquitoes carrying EEE have been found in Rhode Island and Connecticut, near the Massachusetts border.

While anyone can become severely ill or die from EEE, people under the age of 15 are more susceptible. The first symptoms are typically a fever, stiff neck, headache, and lack of energy. Sick people begin exhibiting symptoms between three and 10 days after getting bit by an infected mosquito. 

Those exhibiting symptoms should immediately contact a health care provider, as the disease is aggressive and patients can decline quickly. Some have been known to go into a coma within a week, according to DPH. 

There is no direct treatment for EEE, according to DPH. About half of the people who get EEE in Massachusetts die from the disease. Few people recover completely, and many are permanently disabled. 

“While EEE is a rare disease, it can cause severe disease resulting in hospitalization and death,” Public Health Commissioner Robert Goldstein said in a statement. “We want people to take this information seriously and follow advice to prevent mosquito bites. In this case, evidence suggests that staying indoors between the hours of dusk and dawn can decrease the risk from EEE. Risk is high enough in several towns that we recommend rescheduling outdoor events.”

Luckily, EEE is very rare. It was first found in Massachusetts in 1938, and only 115 cases have been reported since. It can be spread anywhere in the state, but most cases are found in Bristol, Plymouth, and Norfolk counties. 

Every 10 to 20 years an outbreak occurs in the state. An outbreak will usually last two or three years, according to DPH. The last outbreak occurred in 2019, when 12 people were infected and six died. In 2020, five cases were detected and one person died. There were no human cases in 2021 or 2022. 

The virus that causes EEE is often found in birds, which normally do not show signs of illness. Mosquitoes become infected when they bite the birds and can in turn spread it to humans or other animals. Humans do not spread the virus. 

The best way to avoid EEE is to avoid mosquito bites. Officials recommend insect repellent with DEET, long clothes that cover exposed skin, and staying inside during the peak mosquito hours from dusk to dawn. People should consider rescheduling outdoor activities that occur at night or in the early morning, officials said. Residents should also dispose of any standing water around their homes, as this is where mosquitoes breed. 

West Nile Virus, which is also spread by mosquitoes, was found in humans in Massachusetts for the first time this year in late August.