Massachusetts Man Reportedly in a Coma After Contracting Brain Infection From a Mosquito

A rare, sometimes fatal viral infection spread by mosquitoes has resurfaced in Massachusetts—and has likely sent at least one man into a coma. Over the weekend, the Massachusetts Department of Public Health reported that a local resident contracted the Eastern equine encephalitis (EEE) virus. Dozens of communities remain at critical or high risk for the virus, and residents are being advised to stay indoors at night.

Massachusetts health officials have not named the victim, though they did note that he is a resident of Plymouth County over the age of 60. WCVB 5 reported Tuesday that a woman claiming to be the man’s daughter in a Facebook post said that he had fallen into a coma as a result. The man is the first confirmed human case of EEE reported since 2013.

“Today’s news is evidence of the significant risk from EEE and we are asking residents to take this risk very seriously,” said public health commissioner Monica Bharel in a statement released Saturday. “We will continue to monitor this situation and the impacted communities.”

EEE, as we’ve written before, is an infrequent but potentially devastating threat to people. The natural life cycle of the virus involves only mosquitoes and birds, and its primary mosquito carrier tends to live away from humans. But other human-dwelling mosquitos can catch it from infected birds and then infect humans. Most human infections of the virus aren’t serious, but the few that reach the brain can quickly turn fatal or cause lasting neurological symptoms. Currently, there is no specific treatment nor vaccine for EEE.

The absolute risk for EEE remains very rare. There are an average of seven cases of neurological infections caused by the virus reported annually, and just six cases were reported in 2018, according to the Centers for Disease Control and Prevention. For comparison, the West Nile virus, the most common mosquitoborne disease in the U.S., caused at least 1,600 similar cases in 2018.

But so long as people live in close proximity to mosquitoes, EEE is a possible danger to anyone. The areas most at risk for EEE are along the East Coast. Last July, health officials in Florida reported that the virus was spotted in chickens. This Monday, health officials in Connecticut reported mosquitoes in the state had recently tested positive for both EEE and West Nile.

In Massachusetts, health officials declared nine communities to be at critical risk for EEE, and another 15 to be at high risk. They subsequently commenced aerial spraying in some of these areas over the weekend, and recommended that people use “mosquito repellent and consider staying indoors during the dusk to dawn hours to reduce exposure to mosquitoes.”