In July 1976, the American Legion held a convention at the Bellevue-Stratford Hotel in Philadelphia to celebrate the country's bicentennial. Within two days after the start of the event, one veteran after another became ill with an acute pneumonia illness. Ultimately, 221 patients were stricken, and 34 patients eventually died of this mysterious epidemic which came to be known as Legionnaires' Disease.

There was pandemonium once word hit Congress and the White House because the government feared the epidemic to be the beginning of an influenza pandemic known as the Swine Flu, which was already racing through Asia. President Ford was so frightened he even signed the National Swine Flu Immunization Program of 1976, to ensure mass immunization for all American citizens, however, the Swine Flu possibility was soon excluded.

During the Fall of 1976, imaginations soared with proposed etiologies from scientists, physicians, media personnel, and the public. Theories ranged from nickel carbonyl intoxication and viral pneumonia to communist or pharmaceutical company conspiracies against the American veterans. The CDC investigation soon expanded--all the disease survivors and their available relatives, and over 4,400 Legionnaires and their families were questioned, and cadavers were autopsied at the microscopic level.

By September 1976, the focus of the investigation shifted entirely to the Bellvue-Stratford Hotel. The CDC team collected numerous samples from the air, water, soil, dirt and materials from the hotel and its surroundings. However, these samples tested negative for a questionable microbe or toxic chemical. Finally, on January 18,1977, it was announced that Joseph McDade and team isolated the bacterium that causes Legionnaires' Disease. McDade couldn't grow the bacteria for reasons to be discovered, yet he succeeded in obtaining evidence of its existence and pathogenesis through a series of experiments.

Further analysis revealed that the bacteria thrived in the Bellevue-Stratford hotel's cooling tower. From that water supply the hotel derived its air conditioning and the bacteria were actively pumped into the hotel. Since 1976, air conditioning changed, with federal agencies all over the world requiring more stringent cleaning and hygiene provisions for cooling towers and large scale air conditioning systems.


Garrett, Laurie. The Coming Plague: Newly Emerging Diseases in a World Out of Balance. New York: Farrar, Straus, Giroux, 1994.

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