Aerial treatment to combat Eastern Equine Encephalitis (EEE) in 14 Michigan counties has ended, the Michigan Department of Health and Human Services (DHHS) announced Tuesday.
The treatment area spanned more than 557,000 acres in those 14 counties, according to a news release. Allegan, Barry, Berrien, Calhoun, Cass, Jackson, Kent, Lapeer, Livingston, Montcalm, Newaygo, St. Joseph, Van Buren and Washtenaw counties were all sprayed.
EEE is a mosquito-borne disease with a 33% fatality rate. Individuals bitten by EEE-positive mosquitoes can be infected with the virus. In severe cases, the virus can cause neurological damage and death.
Prior to treatment beginning on Sept. 30, the state confirmed 39 cases of EEE in animals and 10 in humans, resulting in four fatalities.
More human EEE cases have been confirmed in one year than in the past decade, according to Dr. Joneigh Khaldun, an MDHHS chief medical executive and chief deputy for health.
“We chose to conduct aerial treatment to protect the health and safety of Michiganders,” Khaldun said. “We also continue to urge communities and residents to take precautions against mosquito bites as the risk of EEE remains until the first hard frost.”
The decision to conduct aerial treatment raised concerns about non-threatening insects that could be harmed. As reported by the Detroit Free Press, pesticides used to kill EEE-carrying mosquitoes can also kill other insects, including the endangered or threatened bees, butterflies and moths.
Further aerial treatments are not planned because of the onset of cooler, unfavorable weather conditions. The aerial treatment is most effective when temperatures stay above 50 degrees, MDHHS said.
As of Oct. 1, mosquitoes carrying EEE were still active in Southwest Michigan, according to the department. The department recommends residents use insect repellent, avoid outdoor activity during dusk to dawn hours, empty pools of standing water and wear long-sleeved clothing or use nets to reduce exposure to mosquito bites.