EEE detected in mosquito samples; Grafton at moderate risk


EEE detected in mosquito samples; Grafton at moderate riskGRAFTON – The Massachusetts Department of Public Health has announced that Eastern equine encephalitis has been detected in additional mosquito samples collected on Sept. 11 in Sutton and Southbridge.

These findings raise the EEE risk level to high in Douglas, Dudley, Oxford, Southbridge, Sutton and Webster, and to moderate in Auburn, Charlton, Grafton, Millbury and Northbridge.

The first EEE-positive mosquitoes in Massachusetts in 2023 were announced on Sept. 1 from Douglas and Southbridge. There have also been mosquitoes with EEE and a donkey with EEE infection identified in Rhode Island and EEE-positive mosquitoes in Connecticut close to the Massachusetts border. No human or animal case of EEE has been detected in Massachusetts so far this year.

“While EEE is a rare disease, it can cause severe disease resulting in hospitalization and death,” said Public Health Commissioner Robert Goldstein. “Risk is high enough in several towns that we recommend rescheduling outdoor events.”

EEE is a rare but serious and potentially fatal disease that can affect people of all ages. EEE is generally spread to humans through the bite of an infected mosquito. There were 12 human cases of EEE in Massachusetts in 2019 with six deaths, and five human cases with one death in 2020. 

It is recommended to use insect repellent when outdoors. The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning in areas of high risk.

Wearing long sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by draining or discarding items that hold water. Check rain gutters and drains. Empty unused flowerpots and wading pools and change the water in birdbaths frequently.

Keep mosquitoes outside by having tightly fitting screens on all windows and doors.

More information, including all WNV and EEE positive results, can be found at

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