A sixth Massachusetts resident -- the second person in Essex County this season -- has been diagnosed with Eastern equine encephalitis, according to Amesbury health officials who say they’ve been notified by the state that a resident of their city has been sickened by the mosquito-borne virus.

In a statement Wednesday, Amesbury Mayor Thatcher W. Kezer III notified residents of a new ban on all outdoor activities on city property from 5 p.m. until 9 a.m. until further notice. He also said that the regional mosquito control authority will be spraying pesticide across the entire North Shore city, which abuts the New Hampshire border, on Thursday evening.

The statement did not say when the resident became ill or whether the person was infected in Amesbury.

Anne Roach, a spokeswoman for the Massachusetts Department of Public Health, declined comment because state health officials have not yet concluded their investigation of the case.

State officials on Tuesday announced that an Essex County man in his 70s was hospitalized with Eastern equine, commonly known as EEE. Separately, officials in Georgetown confirmed the man was a resident of their town. Georgetown officials banned all outdoor activities on town property from 3 p.m. until 9 a.m, and notified residents that the entire town would be sprayed Wednesday evening.

State health officials have urged all residents to guard against mosquito bites by using insect repellant, covering up exposed skin, and avoiding outdoor activities at dusk and nighttime when mosquitoes are most active.