The Illinois Department of Public Health (IDPH) is investigating two cases of Legionnaires’ disease in patients possibly exposed at Mercy Hospital & Medical Center in Chicago, and a report of Legionella in the facility’s water system.  The investigation is currently limited to this facility; the general public is not at risk. IDPH, along with the Chicago Department of Public Health (CDPH), were onsite Thursday to evaluate the reported presence of Legionella in the hospital’s water system and collect environmental samples for laboratory testing. Both agencies continue to collect information and investigate. IDPH has provided the facility with information to give to patients and families about Legionella. Additionally, the facility is conducting active surveillance to identify other potential cases and to ensure appropriate testing and clinical management.  Mercy Hospital & Medical Center is working with a water management team, IDPH and CDPH to strengthen its water management practices. The facility has already put protective measures in place like flushing the water system, altering or replacing water fixtures, and placing filters on sinks.  More information about Legionnaires’ disease can be found on the IDPH website and the Centers for Disease Control and Prevention website.