By Sarah N. Mattero Globe Correspondent

Mosquitoes infected with Eastern equine encephalitis (EEE) have been detected in the state for the first time this year, the Massachusetts Department of Public Health said Wednesday.

The mosquito samples were collected earlier this week in Easton and two of the four positive samples came from a mammal-biting type of mosquito, meaning people are at risk of being infected through bites from the insect.

“Today is our first indication this year that EEE is circulating in our environment, and it’s circulating early,” said State Epidemiologist Dr. Al DeMaria “This is also an important reminder for individuals to take simple, common-sense steps to avoid getting bitten by mosquitoes.”

State health officials have raised the threat level of mosquito-borne illness in the towns of Easton, Raynham, and Taunton from “moderate” to “high,” prompting state and local officials to begin discussions about mosquito-control efforts, which could range from canceling events to aerial spraying.

“As of right now, all activities on town and school properties must cease immediately from dusk to a half hour after dawn until further notice,” said Alan Perry, a Raynham health agent. “The town is advising all outdoor activities on all properties be curtailed during those hours.”

Mosquitoes infected with West Nile virus have also been seen this year in Massachusetts. Although there have been no human cases of West Nile or EEE so far, new state guidelines allow aerial spraying to occur earlier and more often to battle mosquito-borne illness. The state was criticized by some residents of southeastern Massachusetts for not proactively spraying pesticides last summer and putting residents at risk. A Raynham man died of EEE last September, one of two people known to have been infected in Massachusetts last year. The other was a tourist from out of state.