A New Hampshire resident who tested positive for the mosquito-borne infection eastern equine encephalitis virus has died, health authorities in the state said.

The Hampstead resident’s infection was the first in the state in a decade, the New Hampshire Department of Health and Human Services said Tuesday. The resident, whom the department only identified as an adult, had been hospitalized due to severe central nervous system symptoms, the department said.

About a third of people who develop encephalitis from the virus die from the infections, and survivors can suffer lifelong mental and physical disabilities. There is no vaccine or antiviral treatment available. There are typically about 11 human cases of eastern equine encephalitis in the U.S. per year, according to the U.S. Centers for Disease Control and Prevention.