(AP) – A New Hampshire resident infected with the mosquito-borne Eastern equine encephalomyelitis virus has died, state health officials said.

The Hampstead resident’s infection is the first in the state in 10 years, the New Hampshire Department of Health said Tuesday. The resident, whom the department identified only as an adult, was hospitalized for severe central nervous system symptoms, the department said.

About a third of people who develop encephalitis due to the virus die from the infection, and survivors can suffer lifelong mental and physical disabilities. There is no vaccine or antiviral treatment for infections, which cause flu-like symptoms and can lead to severe neurological disease and inflammation of the brain and the membranes surrounding the spinal cord.

“If it causes an infection, it’s very, very serious. Even though it’s a very rare infection, we don’t have a treatment for it,” said Dr. Richard Ellison, an immunologist and infectious disease specialist at the University of Massachusetts Memorial Medical Center. “If someone contracts it, all we can do is provide supportive care, and it can kill people.”

Nationally, the burden of Eastern equine encephalomyelitis can vary from year to year. There are usually about 11 human cases per year in the U.S., according to the U.S. Centers for Disease Control and Prevention. Last year, there were seven cases nationwide, but there were more than 30 in 2019, a historically bad year in which at least a dozen patients died, according to federal data.

The 2019 outbreak included six deaths among 12 confirmed cases in Massachusetts, and the outbreak continued the following year with five more cases and one more death. Two of the three people infected in New Hampshire in 2014 died.

This year, according to the CDC, human infections have been confirmed in New Jersey, Wisconsin, Massachusetts and Vermont in addition to New Hampshire.

The New Hampshire Health Department said the virus was also detected in a horse and several mosquito swarms in New Hampshire this summer. Mosquitoes carrying the virus can sometimes be found in developed areas that were once swampland, where they still find habitat, Ellison said.

Health officials in states where mosquito-borne infections are prevalent urge people to take precautions and prevent mosquito bites by using mosquito repellent, wearing long sleeves and pants, and avoiding outdoor activities in the early morning and evening when mosquitoes are most active. It is also important to remove standing water where mosquitoes breed.

“Given the positive mosquito samples, we believe there is an increased risk of EEEV infection in New England this year. The risk will persist into the fall until a hard freeze arrives to kill the mosquitoes. Everyone should take steps to avoid mosquito bites when outdoors,” said New Hampshire epidemiologist Dr. Benjamin Chan.

In Massachusetts, several towns have urged residents not to go outside at night this summer due to fears of the virus, one of several diseases that can be transmitted to humans by mosquitoes. Massachusetts authorities planned to begin spraying mosquito repellent in some communities on Tuesday to prevent the spread.

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