Updated

Public health officials in Massachusetts and Rhode Island have announced this summer's first case of eastern equine encephalitis in a person.

Citing privacy, officials identified him Sunday only as a Rhode Island man in his 20s from Newport County. He is in critical condition.

Officials say his exposure to a mosquito carrying the encephalitis likely occurred in southeastern Massachusetts, which has been identified as an area of high risk. Officials say his symptoms first occurred August fifth, before aerial spraying.

Officials say aerial spraying from August fifth to seventh has reduced the mosquito population by 80 percent and the number of mammal-biting mosquitoes by 90 percent. Mammal-biting mosquitoes pose the greatest risk to humans.