On Aug. 27, 2024, the New Hampshire Department of Health and Human Services (DHHS) announced they have identified an adult from Hampstead, New Hampshire who tested positive for Eastern Equine Encephalitis Virus (EEEV) infection, was hospitalized due to severe central nervous system disease, and has passed away due to their illness. DHHS offers our sympathies to the individual’s family and friends.

EEEV is a rare but serious disease transmitted to people by infected mosquitos. The last reported human EEEV infection in New Hampshire was in 2014, when DHHS identified three human infections, including two fatalities. In addition to the person with EEEV infection announced today, EEEV has been detected in one horse and seven mosquito batches   in New Hampshire so far this summer. EEEV has also been detected in neighboring states, including in Massachusetts (one person, one horse, and 69 mosquito samples) and Vermont (one person and 47 mosquito samples).  

EEEV can cause flu-like symptoms such as fever, chills, muscle aches, and joint pain. EEEV can also cause severe neurological disease, such as inflammation of the brain and membranes around the spinal cord (i.e. encephalitis and meningitis). Approximately one-third of all people who develop encephalitis from EEEV die from their infection, and many others experience life-long physical or mental impacts. There is no vaccine or antiviral treatment for EEEV.