Seven people have died from Legionnaires’ disease at the Illinois Veterans’ Home in Quincy, IL, as of Sept. 4, the Illinois Department of Public Health reports. Fifty cases have been reported at the retirement community, which offers memory, domiciliary and skilled nursing care for veterans and their spouses.

All of the residents who died had underlying medical conditions, putting them at greater risk, according to health officials.

The veterans home first reported eight confirmed cases of the disease on Aug. 27. “Legionnaires’ disease can be a dangerous illness, especially in older adults who have weaker immune systems,” Nirav D. Shah, MD, JD, health department director, said at the time. The home may see more cases, and perhaps more deaths, Shah noted, because the incubation period for Legionnaires’ disease can be up to two weeks.

Three epidemic intelligence service officers and one environmental health specialist from the Centers for Disease Control and Prevention arrived at the home Aug. 31 to work with veterans affairs and public health officials. The CDC also is providing laboratory support from its headquarters in Atlanta.

Legionella bacteria grow in areas of warm water. To be infected with the bacteria, a person must inhale contaminated water vapor. Most cases of Legionnaires’ disease can be traced to plumbing systems where conditions are favorable for Legionella growth, but cases also have been traced to broken air conditioners, small decorative yard fountains and other sources.

Also in August, two residents of a senior living community in Florida were sickened with pneumonia associated with the Legionella bacteria.