CDC's Joseph McDade Identified Legionnaires' Bacterium After 6-Month Hunt, Tying 1976 Deaths to Cooling Towers
Updated
Updated · The Philadelphia Inquirer · Aug 1
CDC's Joseph McDade Identified Legionnaires' Bacterium After 6-Month Hunt, Tying 1976 Deaths to Cooling Towers
3 articles · Updated · The Philadelphia Inquirer · Aug 1
Summary
January 1977 testing finally showed the 1976 Philadelphia Legionnaires’ outbreak was caused by a previously unrecognized bacterium, after more than six months of failed toxin and virus theories.
Joseph McDade, a CDC microbiologist, made the breakthrough by reexamining slide samples on a hunch and spotting unfamiliar microbes that had been missed in tens of thousands of earlier tests.
Investigators later concluded airborne water mist from the Bellevue-Stratford Hotel’s air-conditioning cooling towers spread the bacteria to American Legion conventioneers and some people who passed nearby.
The outbreak began after about 2,000 Legion delegates met in late July 1976; by mid-August, 29 people were dead and about 200 were sickened, while the hotel’s business collapsed.
The discovery also linked the organism to earlier unsolved outbreaks in 1965, 1968 and 1974, showing Legionnaires’ disease had existed before Philadelphia gave it its name.