Tick-borne diseases reported every month of the year and in every Illinois county

MedicalXpress | июн 29, 2026

A new analysis of state health department data reveals that more than 6,400 Illinois residents were diagnosed with tick-borne diseases from 2004 to 2022. The most commonly reported infections in the state are Lyme disease, occurring across Illinois but at higher rates in northern counties; anaplasmosis, reported most often in northern and southern counties; ehrlichiosis, seen most often in southern Illinois; and spotted-fever group rickettsioses, serious and sometimes deadly infections that also are more prevalent in southern Illinois.