According to officials, the mosquitoes were found in trap sites in the towns of Chester, East Lyme, and Hampton.
To date, three people have died in Connecticut from the disease.
The latest person to die during the third week of September lived in the East Haddam area, said State Epidemiologist Dr. Matthew Cartter said.
The person, in their 60s, became ill during the second week of September, the Connecticut Department of Health said.
Most people infected with EEE have no apparent illness, however, some can be very ill. Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin with the sudden onset of headache, high fever, chills, and vomiting 4 to 10 days after a mosquito bite.
Although mosquito numbers are declining with the onset of cool weather, health officials said there is a continued risk for mosquito-borne diseases until the first hard freeze when mosquito activity ends.
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