Enlarge / An entomologist for the Louisville Metro Department of Public Health and Wellness in a swampland area on August 25, 2021, in Louisville, Kentucky, collecting various mosquito species and testing the samples for mosquito-borne diseases, such as EEE. (credit: Getty |)

New York is facing an unusual boom in mosquitoes toting the deadly eastern equine encephalitis (EEE) virus, which has already led to one rare death in the state and a declaration of an "imminent threat" by officials.

While the state's surveillance system typically picks up EEE-positive mosquitoes in two or three counties each year, this year there have been 15 affected counties, which are scattered all across New York, State Health Commissioner James McDonald said this week.

"Eastern equine encephalitis is different this year," McDonald said, noting the deadly nature of the infection, which has a mortality rate of between 30 and 50 percent. "Mosquitoes, once a nuisance, are now a threat," McDonald added. "I urge all New Yorkers to prevent mosquito bites by using insect repellents, wearing long-sleeved clothing, and removing free-standing water near their homes. Fall is officially here, but mosquitoes will be around until we see multiple nights of below-freezing temperatures."