Testing of the public water supply and other potential sources has not led investigators for the Illinois Department of Public Health and the Illinois EPA to the cause of a cluster of three Legionnaires disease cases in the small Shelby County town of Findlay.

The three infected individuals reported symptoms that started in late July and early August. IDPH officials say that a definitive source of Legionella is rarely determined through environmental investigation. Legionnaires’ disease is a serious lung infection, and disease transmission primarily occurs through breathing in Legionella-contaminated, aerosolized water.