Eastern Equine Encephalitis: Wisconsin Data

The first human case of Eastern equine encephalitis (EEE) in Wisconsin was identified in 1964.

EEE is very rare in Wisconsin, but can lead to severe illness or even death. There have been seven human cases of EEE reported in Wisconsin from 1964 to 2022.

Four of those cases occurred during 2020 through 2022.

You can see this year's statewide data for EEE in the table and the map at the top of this page. To date, there have been no reported human or animal cases of EEE in 2023. Case numbers are updated routinely during mosquito season.

Counties with reported cases of EEE in horses or in humans indicate that some mosquitoes in the area are infected with the virus and may spread EEE to other humans or animals.

Summary data for previous years can be found at the bottom of this page.

For information on national data, visit the CDC (Centers for Disease Control and Prevention) Epidemiology and Geographic Distribution page for Eastern Equine Encephalitis.

* Probable cases have presumptive positive laboratory results without confirmatory testing at CDC.
** The deaths are included among the confirmed and probable cases.