VERNON HILLS (CBS) — One person has died and two others have been diagnosed with Legionnaires’ disease at Brookdale Senior Living in Vernon Hills, county health officials said.

“Since receiving the reports of Legionnaires’ disease cases late Monday, the Lake County Health Department has been working closely with the Illinois Department of Public Health and Brookdale staff to investigate potential sources of contamination and to identify individuals who may have been exposed to Legionella bacteria,” said Mark Pfister, Executive Director for the Lake County Health Department.

The source of contamination at the Brookdale facility on Milwaukee Avenue is under investigation by health experts.

Legionnaires’ disease is a type of severe pneumonia caused by Legionella bacteria. It is treatable with antibiotics. Most people who get sick  make a full recovery. However, about 1 out of 10 people who get Legionnaires’ disease will die from the infection.

Most healthy people do not get Legionnaires’ disease after being exposed to Legionella bacteria. People at increased risk of getting sick include:

  • People ages 50 years or older
  • Current or former smokers
  • People with a chronic lung disease
  • People with weak immune systems or who take drugs that weaken the immune system
  • People with cancer
  • People with underlying illnesses such as diabetes, kidney failure, or liver failure

Legionella bacteria grow in areas of warm water. In order to be infected with the bacteria, a person must breathe in a mist or vapor that contains the bacteria. There is no evidence that the Legionella bacteria are spread from person-to-person.

Brookdale spokeswoman Heather Hunter said the source of the outbreak is unknown, but the facility has turned off all water fountains, and closed the pool and spa to prevent any further spread of Legionalla bacteria. The facility also is flushing water lines, cleaning shower heads, and adding filters.

“We are working with the Lake County Health Department, the Illinois Department of Health and a national water treatment company and are following their protocols and recommendations regarding Legionella bacteria. At this time, no one knows the source of the bacteria; however, we felt it necessary to take a proactive approach to help stop any spread of this bacteria,” Hunter stated in an email.

“Our greatest concern is the health of the residents of our community, so we have responded quickly and proactively to this situation,” Hunter added.