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Legionnaires’ disease outbreak in Philadelphia in 1976 was mysterious and deadly – 50 years later, scientists know the cause but outbreaks continue
Editorial

Legionnaires’ disease outbreak in Philadelphia in 1976 was mysterious and deadly – 50 years later, scientists know the cause but outbreaks continue

Charles Nathan Haas and Robert Promisloff
The Conversation
19 Jun 2026

Abstract

Disease
Soon after Philadelphia hosted America’s bicentennial celebrations in late July 1976, more than 200 attendees of the American Legion Convention at the Bellevue-Stratford Hotel in Philadelphia fell ill with pneumonia symptoms, including fever, cough and trouble breathing. Thirty-four of them died. One of us was a newly minted pulmonary fellow at Hahnemann University Hospital. The hospital was just a mile from the hotel and received some of the first cases. At the time, no one knew what caused the illnesses. Scientists considered bacterial or viral infection, heavy metal toxins or some combination of environmental causes.

Details

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