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226,000 total acres treated for mosquitoes to date; aerial treatment resumes Monday Barry County resident confirmed to have EEE and animal cases increase to 30

September 18, 2020
Contact: Lynn Sutfin, 517-241-2112

LANSING, Mich. – A second night of aerial treatment to protect Michiganders from Eastern Equine Encephalitis (EEE) has resulted in more than 226,000 total acres being completed to date, announced the Michigan Department of Health and Human Services (MDHHS) today.

Aerial treatment conducted on Thursday, Sept. 17, treated nearly 69,000 acres in Blocks 5-1, 6-2, 7-1 and 10-1. Due to nighttime temperatures predicted to be below 50 degrees F over the weekend, aerial treatment will resume on Monday, Sept. 21. The mosquito that carries EEE does not fly at temperatures below 50 degrees F. However, Michiganders need to continue taking precautions as mosquitos are present and will remain active until there is a hard freeze, equivalent to the temperature dropping below 28 degrees F for an extended period of time. 

“Treatment is being conducted to protect the health and safety of Michiganders in the affected areas,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health at MDHHS. “EEE is a potentially deadly mosquito-borne virus affecting both people and animals and we need Michiganders to continue taking precautions against mosquito bites.”

A new horse case has been confirmed in Calhoun County, bringing the total to 29 cases of EEE in horses in 12 counties as of Sept. 17. Additionally, a deer in Allegan County has been diagnosed with EEE. Impacted counties are now Allegan, Barry, Calhoun, Clare, Ionia, Isabella, Jackson, Kent, Livingston, Mecosta, Montcalm, Newaygo and Oakland. Testing at the MDHHS Bureau of Laboratories has also confirmed EEE in a Barry County resident.

The newly discovered EEE cases in horses have expanded or added treatment blocks to the overall plan in Calhoun, Ionia, Jackson, Kent, Livingston and Montcalm counties. More information is being collected on the Allegan County deer case and any changes to the treatment plan will be announced at a later date. Please refer to the County-level Aerial Treatment Maps for more details of the identified zones’ locations. 

For more information about EEE, visit

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