CHICAGO (AP) — An outbreak of Legionnaires’ disease at a senior living center in suburban Chicago has left one resident dead and two others sickened, health officials said Wednesday.

The Lake County Health Department said in a news release that it has confirmed three cases of the disease, a type of severe pneumonia caused by the Legionella bacteria, at Brookdale Senior Living in Vernon Hills. The release says staffers at the facility were notifying residents and others who may have been exposed to the bacteria and were working with state and county health departments to determine “potential sources of contamination.”

“We urge any residents and visitors of the Brookdale facility who are currently experiencing pneumonia symptoms — cough, shortness of breath, headache, muscle aches and fever — to see a doctor right away for testing,” Dr. Sana Ahmed, the health department’s medical epidemiologist, said in the release. “Early treatment of Legionnaires’ disease reduces the severity of the illness and improves your chances for recovery.”

The health department would only say that the person who died was over the age of 80 as were the two people who became sick, and that all three became ill within the last month.

A spokeswoman for Brookdale said in a statement that the facility has turned ff all fountains and closed the pool and spa in response to the disease, which is caused by inhaling water vapor infected with Legionella bacteria.

Spokeswoman Heather Hunter also wrote, “We are following the recommendation of national water treatment company regarding flushing water lines, cleaning shower heads and adding filters.”

Last year, a state audit was critical of the Department of Public Health and Veterans’Affairs for delays in taking action and notifying nursing staff and the public about a 2015 outbreak at an Illinois veterans’ home in Quincy that left 13 elderly residents dead. The same audit contradicted former Gov. Bruce Rauner’s contention that his administration had done everything that federal experts recommended it do to remedy the crisis.