Mass. officials say man in his 80s contracted EEE in state's 1st human case since 2020

Massachusetts has identified its first human case of Eastern equine encephalitis, or EEE, since 2020.

The patient, a man in his 80s, was exposed to the mosquito-borne illness in Worcester County, the Massachusetts Department of Public Health said Friday.

Health officials in Massachusetts have been urging caution around mosquitoes after EEE and West Nile virus were detected in the insects earlier this summer. The DPH said on Aug. 6 that the first animal case of EEE and the first human case of West Nile in 2024 had been identified.

EEE is rare, but poses a serious threat to infected people of all ages.

Twelve people are known to have contracted EEE in Massachusetts in 2019. Six of those people died. In 2020, five people were infected, one of whom died. There were no human cases in the following three years.

As a result of the diagnosis, health officials raised the risk level for EEE to critical in Douglas, Oxford, Sutton and Webster. They are the only four communities in the state with the classification.

Massachusetts identifies high risk of EEE in Carver, Dudley, Middleborough, Northbridge, Plymouth and Uxbridge.

There are 23 communities with moderate risk of EEE: Amesbury, Auburn, Bridgewater, Charlton, Grafton, Groveland, Halifax, Haverhill, Kingston, Lakeville, Leicester, Mendon, Merrimac, Millbury, Millville, Newburyport, Plympton, Rochester, Salisbury, Southbridge, Upton, Wareham and West Newbury.

"The risk from EEE is high in parts of Plymouth County and critical in parts of Worcester County," State Epidemiologist Dr. Catherine M. Brown said in a statement shared by the DPH. "In addition to recommending that people use mosquito repellent with an EPA-registered active ingredient and clothing to reduce exposed skin, we also recommend that evening outdoor events be rescheduled to avoid the hours between dusk and dawn. The mosquitoes most likely to spread EEE are most active during the dusk to dawn hours."

The DPH has interactive maps showing risk levels of EEE and West Nile virus.

Massachusetts Department of Public Health

"This is the first time we have seen a person infected with EEE in Massachusetts since 2020," Public Health Commissioner Robbie Goldstein said in a statement. "EEE is a rare but serious disease and a public health concern. We want to remind residents of the need to protect themselves from mosquito bites, especially in areas of the state where we are seeing EEE activity."

Much of the state is also at moderate risk for West Nile virus.

Massachusetts Department of Public Health

The DPH has noted that August and September are months of particular concern for mosquito-borne illnesses in Massachusetts.

Officials expect the mosquito population to increase throughout the summer and recommend, among other prevention techniques, avoiding outdoor activities in dawn and dusk, when mosquitoes are most active.

People are also urged to drain standing water, where mosquitoes lay eggs, and use screens in their homes. They should also be careful to protect their animals.

The Department of Public Health says people can call its Division of Epidemiology at 617-983-6800 for more information about the mosquito-borne illnesses.