Over two dozen cities and towns in Massachusetts are at “critical” risk for Eastern Equine Encephalitis, or EEE, — a rare but deadly mosquito-borne virus that took the life of a Fairhaven woman earlier this week.

A map posted by the state Department of Public Health Thursday shows another 37 communities are labeled at “high” risk, while dozens more are considered at a “moderate” risk level.

-Massachusetts Department of Public Health —

The Commonwealth is currently experiencing its first outbreak of EEE since 2012. The virus, which comes around every 10 to 20 years, has already been contracted by four people this month, including Laurie Sylvia, who died after being hospitalized with the infection.


EEE, which spreads through infected mosquitos often found in and around freshwater, hardwood swamps, can trigger symptoms such as brain swelling, fever, and coma, according to the Centers for Disease Control and Prevention.

“Death usually occurs 2 to 10 days after onset of symptoms but can occur much later,” the CDC says. “Of those who recover, many are left with disabling and progressive mental and physical sequelae, which can range from minimal brain dysfunction to severe intellectual impairment, personality disorders, seizures, paralysis, and cranial nerve dysfunction. Many patients with severe sequelae die within a few years.”

There is no vaccine for EEE.

While the state has already carried out aerial spraying for mosquito control to combat the spread, DPH spokesperson Ann Scales said the department does not reduce its critical and high risk level labels for cities and towns even after a flyover occurs.

“The reason is, although aerial interventions are anticipated to help reduce the risk, they will not eliminate it and it also serves as a reminder for residents and communities to take all appropriate precautions to reduce mosquito bites,” she told Boston.com Monday.

Officials are urging the public to avoid being outdoors at night during peak mosquito times, to use insect repellent, and to wear long-sleeved clothing, among other precautions.