A New Hampshire resident recently died from eastern equine encephalitis virus (EEE virus), and the virus is spreading across five New England states. Neither the virus nor the disease, which remains rare, are new. Yet, the pathogen's ability to cause devastating infections in some people and barely any symptoms in others continues to befuddle scientists.
Virologist Jonathan Abraham, associate professor of microbiology in the Blavatnik Institute at Harvard Medical School and an infectious disease specialist at Brigham and Women's Hospital, has studied the virus in detail. In studies published in Nature in 2021 and 2024, Abraham and team mapped the structure and behavior of the cell receptors—the entryways on the surfaces of cells—that allow EEE virus and similar viruses to infect their hosts and cause mischief. Abraham spoke with Harvard Medicine News about the knowns and unknowns of EEE virus and the trajectory of the latest outbreak.
Do we have any sense about what proportion of the people who get bitten by an infected mosquito go on to develop symptoms of the disease? Not really, because we currently do not screen for exposure to infection . Many people who are infected develop mild symptoms, such as headache, fever, and general malaise, but they are typically not diagnosed because they never seek care. About two percent of people go on to develop encephalitis, a form of brain infection, which is the most dangerous complication of the disease.
Up to one-third of those w.