Person dies in New Hampshire after contracting EEE as Northeast states warn of mosquito-borne virus

A person in New Hampshire has died after contracting the eastern equine encephalitis virus.

EEE is a rare disease transmitted by mosquitoes; only 11 human cases are reported annually on average, according to the Centers for Disease Control and Prevention. Several people, horses and mosquitoes around the Northeast have tested positive for the disease this summer.

A resident of Hampstead, New Hampshire was hospitalized due to severe central nervous system disease and passed away due to the illness, according to a Tuesday release from the New Hampshire Department of Health and Human Services. The department declined to release the identity or time of death of the individual.

“We believe there is an elevated risk for (EEE) infections this year in New England given the positive mosquito samples identified,” New Hampshire state epidemiologist Dr. Benjamin Chan said in the release. “The risk will continue into the fall until there is a hard frost that kills the (mosquitoes). Everybody should take steps to prevent mosquito bites when they are outdoors.”

‘Take extra precautions’: Massachusetts towns warn about rare, lethal mosquito-borne virus

Officials around the Northeast urge precautions due to EEE risk

While EEE is rare, roughly 30% of cases end in death, and many survivors have ongoing neurologic issues, according to the CDC. The virus is most common around Eastern or Gulf Coast states, and researchers have also warned that climate change is giving rise to mosquitoes as they thrive in warm, humid weather.

The CDC has identified four human EEE cases in 2024, in Wisconsin, New Jersey, Massachusetts and Vermont. The agency did not respond to USA TODAY’s request for updated tracking in light of the New Hampshire case.

EEE has also been found in horses or mosquitoes in several other states including Massachusetts, New York, Rhode Island and Connecticut. Officials in some counties have urged residents to take precautions, and a Massachusetts town even closed public parks and fields from dusk until dawn.

Massachusetts’ most recent outbreak began in 2019 and left six dead.

How to protect yourself from EEE

Eastern equine encephalitis is spread to humans through bites from infected mosquitoes. The virus can cause a fever, headache, vomiting, diarrhea, seizures, behavioral changes, and drowsiness, according to the CDC.

Most people infected with eastern equine encephalitis do not develop symptoms, the CDC said. People of all ages are susceptible to infection, but people over 50 and younger than 15 are at greatest risk.

There is no treatment or vaccine for EEE, but people in high-risk areas can protect themselves by preventing mosquito bites, which are most likely to happen from dusk to dawn. Take precautions to avoid mosquito bites and protect against potential exposure to the mosquito-borne illness:

• Use insect repellent.
• Wear loose-fitting, long-sleeved shirts and pants.
• Use air conditioning and window screens to prevent mosquito bites indoors.
• Dump out containers of water near your home to eliminate breeding grounds.

Contributing: Mike Murphy, Rochester Democrat and Chronicle, Henry Schwan, Telegram and Gazette