Nursing homes and hospitals need to do more to protect their patients from catching Legionnaires’ disease from contaminated water systems in their buildings, federal health officials warned.

An analysis of more than 2,800 cases of Legionnaires’ that occurred in 2015 found that 553 definitely or possibly occurred in a health care facility such as a nursing home or a hospital, according to the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report. Sixty-six patients died from the disease.

“It’s widespread, it’s deadly and it’s preventable,” says Anne Schuchat, the CDC’s acting director.   “This analysis has uncovered a problem that is happening every day in health care facilities around the country and something we can do a lot about,” she says. “This report suggests that in many health care facilities, there’s really just an outbreak waiting to happen.”