Prairie State Wire

The Illinois Department of Public Health (IDPH) has reported the discovery of a tick in Lake County that tested positive for Ehrlichia muris eauclairensis (EME), marking the first such case in the state. EME is a bacterium transmitted through blacklegged tick bites, potentially causing human ehrlichiosis—a serious disease that requires prompt treatment to avoid complications. The IDPH's Vector Control Program has alerted healthcare providers in Northern Illinois to remain vigilant for signs of ehrlichiosis.

The blacklegged tick, also known as a deer tick, was collected on May 17 by staff from the Lake County Health Department. This effort was supported by funding from IDPH’s Environmental Health Tick Surveillance Grant program. Testing by the Centers for Disease Control and Prevention confirmed the presence of EME in the tick. Besides ehrlichiosis, ticks submitted to the CDC are screened for various diseases, including Lyme disease and babesiosis.

Previously, human cases of EME were only documented in Wisconsin and Minnesota since its first identification in Eau Claire County, Wisconsin, in 2009. In Illinois, ehrlichiosis primarily occurs in Southern regions due to Lone star ticks. However, this recent finding indicates that another species—the blacklegged tick—can also transmit ehrlichiosis within the state.

“The discovery of the first tick in Illinois carrying EME, a rare and serious disease, is a great reminder of the importance of our active tick surveillance program in Illinois,” stated IDPH Director Dr. Sameer Vohra. He advised individuals who frequent wooded or brushy areas to regularly check for ticks and seek medical attention if symptoms such as fever or muscle aches develop after exposure.

This announcement precedes the 2024 Illinois Tickborne Disease Conference scheduled for October 22 in Champaign. Organized by IDPH alongside Southern Illinois University School of Medicine and the Illinois Lyme Association, the conference aims to educate healthcare professionals about Lyme and other tickborne diseases.

To prevent tickborne illnesses while outdoors, people are advised to walk on trails' centers away from high grass or leaf litter and wear light-colored clothing for easier detection of ticks. Using EPA-registered insect repellents containing DEET or similar compounds is recommended along with treating outdoor clothing with permethrin.

Regular full-body checks every two to three hours during outdoor activities can help identify any attached ticks promptly. Additionally, placing clothes in a dryer on high heat after outings can effectively kill any remaining ticks.

Further details regarding tick species distribution across counties in Illinois can be accessed via IDPH’s interactive Tick Surveillance Map available online.