Ehrlichiosis: Wisconsin Data

Ehrlichiosis is caused by several species of Ehrlichia bacteria.

The number of reported cases has been increasing in the state. In 2018, Wisconsin had 79 probable and confirmed cases of ehrlichiosis (E. chaffeensis, E. muris eauclairensis, and E. ewingii).

Ehrlichiosis is preventable and treatable.

Below are the statewide data for ehrlichiosis.

For information on national data, visit the Centers for Disease Control and Prevention (CDC) Statistics and Epidemiology page for ehrlichiosis.

Map of Ehrlichiosis cases per 100,000 residents 2018

Ehrlichiosis Data

Historical ehrlichiosis surveillance included human granulocytic ehrlichiosis (HGE) and human monocytic ehrlichiosis (HME). As of 2008, the surveillance case definition changed to classify the disease by two different bacterial infections, Anaplasma phagocytophilum and Ehrlichia species.

Ehrlichiosis Cases in Wisconsin

There are three species of Ehrlichia that cause illness in the U.S. and Wisconsin: E. chaffeensis, E. muris eauclairensis, and E. ewingii.

E. chaffeensis

Chart of total Ehrlichiosis (E. chaffeensis) Cases 2009-2018

E. muris eauclairensis

E. muris eauclairensis is a newer species of Ehrlichia. It was discovered in Wisconsin and Minnesota in 2009.

Graph total cases of Ehrlichiosis (E. muris eauclairensis) cases 2009-2018

E. ewingii

E. ewingii is rare in Wisconsin. There have been two reported cases in the state.

Chart of total Ehrlichiosis (E. ewingii) Cases 2016-2018

Ehrlichiosis Cases Reported by Month and Age

Month of Illness Onset

Graph of average Ehrlichiosis cases by month 2014-2018

Age Group

Graph of average Ehrlichiosis cases by age group (2014-2018)

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The recommendations in this webpage were developed in accordance with Wis. Stat. ch. 252 and Wis. Admin. Code ch. DHS 145.

Last Revised: September 27, 2021