New Hampshire resident dies after testing positive for EEEV in state's 1st human case since 2014

A New Hampshire resident died after being infected with a rare mosquito-borne disease, health officials said Tuesday.

The resident, an adult from Hempstead -- near the southeastern border with Massachusetts -- had tested positive for Eastern Equine Encephalitis virus (EEEV). The patient was hospitalized due to severe central nervous system disease and died of their illness, according to an update from the state's Department of Health & Human Services (DHHS).

This is the first reported human case of EEEV in New Hampshire in a decade after three people contracted the disease in 2014, two of whom died, DHHS said.

It's unclear when the resident, who recently died, first became infected with EEEV. No other details were available including name, age or sex.

In addition to the person infected with EEEV, the virus has also been found in one horse and seven mosquito batches in New Hampshire so far this summer, according to the health department.

Neighboring states have been experiencing similar threats. In Massachusetts, 10 communities were designated as being under high or critical risk of the virus, according to the state's Department of Public Health. Many of the areas began implementing targeted mosquito spraying to protect residents.

Cases of EEEV have been tracked since 2003 and are variable year-to-year but CDC data shows the highest number of cases on record were in 2019 when 38 people across 10 states had this virus. At least 19 people died from the virus in 2019, according to the CDC. In 2019, EEEV was the deadliest reportable arbovirus disease when 50% of people infected died.

"In New Hampshire, mosquitos transmit infections including Eastern Equine Encephalitis Virus, West Nile Virus, and Jamestown Canyon Virus," Dr. Benjamin Chan, New Hampshire's state epidemiologist, said in a statement.

"We believe there is an elevated risk for EEEV infections this year in New England given the positive mosquito samples identified. The risk will continue into the fall until there is a hard frost that kills the mosquitos. Everybody should take steps to prevent mosquito bites when they are outdoors," the statement continued.

EEEV is a rare but serious disease that spreads by bites from infected mosquitoes. It does not spread via touching or droplets from coughing or sneezing, according to the Centers for Disease Control and Prevention (CDC).

Most people who are infected either show mild symptoms or no symptoms at all. However, severe cases usually begin with fever, headache, chills and vomiting before progressing to encephalitis, which is swelling of the brain, or meningitis, which is swelling of the membranes that surround the brain and spinal cord.

Many survivors have ongoing neurologic problems including convulsions, paralysis and intellectual disability, and about 30% of encephalitis cases from this virus result in death.

There are no human vaccines and no treatments specifically for EEEV. The CDC says rest, fluids and over-the-counter pain medications may help relieve some symptoms.

As of Tuesday, four cases have been reported aside from the New Hampshire case -- with one case each in Massachusetts, New Jersey, Vermont and Wisconsin, according to the CDC.

The New Hampshire DHHS said residents can protect themselves by using effective mosquito repellents, wearing long-sleeve shirts and long pants when outside and avoiding outdoor activities when mosquitoes are the most active, including early in the morning and during evening hours.

Additionally, residents are advised to remove standing water from around their homes, which attracts mosquitoes, and to make sure doors and windows have tight-fitting screens.