US Legionnaires' disease cases have risen 5.5-fold since 2000, prompting calls to shift prevention from post-outbreak building responses to source-water management, stronger surveillance and earlier public health action.
Routine water disruptions — including source changes, pipe repairs, chlorine burns and severe weather — can dislodge biofilms and send Legionella downstream, raising risks for hospitals and long-term care facilities unless they get advance warning.
Only about 4% of cases are tied to recognized outbreaks, Hung Cheung said, arguing that an investigation strategy built around those events may miss how the other 96% of sporadic cases are transmitted.
The Alliance to Prevent Legionnaires' Disease is urging tighter coordination among utilities, public health agencies and healthcare facilities, along with clinician awareness after water disruptions and basic maintenance such as flushing hot water tanks.