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Dates That Matter

July 23, 1976

Hundreds of American Legionnaires attending a convention in Philadelphia are stricken by an unknown illness.

 Why does it matter?

Approximately 4,000 members of the American Legion attended a convention, and soon, many of them fell ill with a mysterious respiratory illness. In the end, 250 cases of the pneumonia-like illness were identified and 34 people died of the illness. After a four-month investigation, it was determined that the illness was caused by a bacteria that multiplies in water pipes and air conditioning units. The illness is now called "Legionnaires' disease" and probably affects around 20,000 persons each year. For most, it is not serious, but for smokers and the elderly, the illness can be fatal.

For more information...

Disease Listing, Legionellosis
Medical information from the Center for Disease Control on Legionellosis, or Legionnaires' Disease.

WHO Legionellosis
The World Health Organization's information page on Legionnaires' Disease.