CHICAGO (CBS) — The Illinois Department of Public Health said it has identified people with Legionnaires’ disease in a Chicago nursing home as well as people in McHenry and Lake Counties.

The agency said one cluster involving two people were at the Warren Barr South Loop nursing home.

At least three residents from McHenry and Lake counties were identified in the other cluster where a Walmart in Johnsburg was named “as one common potential exposure,” according to the IDPH. Johnsburg is located in McHenry County.

“The Walmart location has taken action, including turning off the produce water sprayers.  Health officials will continue to investigate any other potential sources and identify other cases of Legionnaires’ disease,” the health department said in a statement.

At the Chicago facility, “the nursing home has taken action, including revising its water management plan, increased environmental sampling, and heightened clinical surveillance,” said the agency. It added that the nursing home is notifying its residents, identified the contacts, staff and “following public health recommendations for ongoing surveillance, mitigation, and remediation.”

Legionnaires’ disease is a serious lung infection people can get through inhaling small droplets of water that have the Legionella bacteria. The health department said most healthy people do not get the disease after being exposed to the bacteria.

Those at risk include people over the age of 50 and have certain risk factors including a weakened immune system, being a former smoker and/or having a chronic disease.

In 2015 a woman died after contracting Legionnaires’ disease at the Warren Barr nursing home. Warren Barr officials said they were following protocols established by the U.S. Centers for Disease Control and Prevention, have retained experts to conduct proper texting, and notified state health officials.