A rare but deadly mosquito-borne disease is causing a Massachusetts city to close its parks and fields every night, and four other cities are urging people not to go outside at night.
They are concerned about eastern equine encephalitis. State health officials announced last week that a man in his 80s had contracted the disease, the first human case found in Massachusetts since 2020.
The city of Plymouth, about 40 miles (64 kilometers) southeast of Boston, announced Friday that it will close outdoor public recreation areas from dusk to dawn every day after a horse in the city was infected with the disease.
Meanwhile, state health officials warned that a cluster of four towns south of Worcester — Douglas, Oxford, Sutton and Webster — are at “critical risk” after an Oxford man contracted the virus.
State and local health officials urged people in those cities to avoid peak mosquito bite times by stopping outdoor activities before 6 p.m. through Sept. 30 and before 5 p.m. thereafter until the first hard frost arrives.
They also advise people in Massachusetts to use mosquito repellent when outdoors and to drain standing water around their homes.
Oxford City Manager Jennifer Callahan wrote in a memo that the family of the man who contracted the virus in mid-August had contacted her office.
“They want people to be aware that this is an extremely serious disease with terrible physical and emotional consequences, regardless of whether the person survives,” Callahan wrote.
She said the infected person had often told his family that he had never been bitten by mosquitoes. But just before he developed symptoms, he told them that he had been bitten. She said the man is still in hospital and is “bravely fighting” the virus.
Callahan said the family is urging people to take public health advice seriously and do their utmost to protect themselves.
The presence of the virus in Massachusetts this year was confirmed last month in a mosquito sample and has since been found in other mosquitoes in the state. An outbreak in 2019 left six dead among 12 confirmed cases in Massachusetts. The outbreak continued the following year with five more cases and one more death.
There are no vaccines or treatments for EEE.
The U.S. Centers for Disease Control and Prevention says that EEE, while rare, is very serious and about 30% of people who get infected die. Symptoms include fever, headache, vomiting, diarrhea and seizures.
Those who survive are often permanently disabled, and few make a full recovery, Massachusetts officials say. The disease is common in birds, and while humans and some other mammals can contract EEE, they do not spread it.
According to the CDC, only a few cases of EEE are reported each year in the U.S., with most infections occurring in the eastern and Gulf Coast states.