Eastern Equine Encephalitis

  • 2020 EEE Outbreak Information

    In late summer and autumn of 2020, Michigan experienced an outbreak of Eastern Equine Encephalitis (EEE).  EEE is one of the most dangerous mosquito-borne diseases in the United States, with a 33 percent fatality rate in people who become ill.  To date, there have been 3 human cases (including one death), and 41 animal cases in Michigan in 2020.

    In an effort to prevent spread of Eastern Equine Encephalitis (EEE), MDHHS conducted aerial mosquito control treatment Sep. 16 - 23 in certain high-risk areas of Michigan.  This treatment was completed successfully and there were no adverse events reported from the aerial treatment. 

    After several hard frosts, the risk of mosquito-borne transmission has dropped and no new transmission of EEE is expected in Michigan until weather warms in the spring.  However, cases from earlier in the year may still continue to be uncovered, leading to an increase in the number of reported cases.

  • EEE 2020

    FAQ :  Eastern Equine Encephalitis and Aerial Treatment 

    Spanish | Arabic

    State EEE Treatment Blocks

    Michigan County Treatment Zones

    MDARD Emergency Rule Amending R 285.637.11

    Why can I not opt-out of aerial treatment this year?

    2020 Press Releases


    Arbovirus Daily Update, including Eastern Equine Encephalitis in Michigan (Updated July 22, 2021):

    2020 Weekly Arbovirus Surveillance Summary