For the first time since 1989, the state of Michigan and local health departments will conduct aerial spraying to combat eastern equine encephalitis (EEE).  The rare mosquito-borne virus has killed three people in Michigan and has been detected across the southern half of the state.

The aerial spraying is scheduled to start Sunday Sept. 29,  and will include 14 counties where EEE has been confirmed in humans or animals. The spraying is weather-dependent.  The counties to be targeted are Allegan, Barry, Berrien, Branch, Calhoun, Cass, Jackson, Kalamazoo, Kent, Lapeer, Montcalm, Newaygo, St. Joseph and Van Buren.

Aerial spraying has recently been done in several states, including Massachusetts and Rhode Island. Michigan is encouraging officials in affected counties to consider postponing or rescheduling evening outdoor events until there’s a hard frost.

The number of U.S. deaths and illnesses from EEE have been higher than usual this year.