CHICAGO — Health officials have identified two new clusters of Legionnaires’ disease in Illinois.

The first, which has impacted people in McHenry and Lake counties, could be linked to a Walmart in Johnsburg. The second has affected Chicago residents at the Warren Barr nursing home at 1725 S. Wabash Ave.

Officials said the two clusters are not connected. Authorities are still trying to pinpoint the sources and identify who may have been exposed.

Warren Barr’s regional director said tests for Legionnaires at the South Loop facility have come back negative. She believes one of the residents could have contracted the disease elsewhere.

Shawn Estoque has lived at the nursing home since June. He said he noticed signs telling residents not to use water for bathing — but had no idea that two residents had been diagnosed with Legionnaires.

“This the first time I’m hearing this, from you guys,” he said. “I knew we couldn’t use the water. I didn’t know it was that serious.”

Legionnaires’ disease is caused by legionella bacteria, which can lead to a severe lung infection. The disease is not spread person-to-person, but can be deadly for those with weakened immune systems. At a state-run veterans’ home in Quincy, more than a dozen people have died since 2015.

Legionnaires is a concern at Warren Barr because the facility focuses on respiratory care.

A spokesperson said the nursing home notified direct relatives of those who tested positive and will place pamphlets about Legionnaires’ disease throughout the facility.

A patient at Warren Barr’s Gold Coast facility died of Legionnaires’ disease in 2015.