1976 Philadelphia Legionnaires' disease outbreak 1976 Philadelphia Legionnaires' disease outbreak The 1976 Legionnaires disease outbreak, occurring in the late summer in Philadelphia, Pennsylvania, was the first occasion in which a cluster of a particular type of pneumonia cases were determined to be caused by the "Legionella pneumophila" bacteria. Previous outbreaks were retroactively diagnosed as being most probably caused by Legionella bacteria. On July 21, 1976, the American Legion opened its annual three-day convention at the Bellevue-Stratford Hotel in Philadelphia, Pennsylvania. More than 2,000 Legionnaires, mostly men, attended the convention. The date and city were chosen to coincide with America’s celebration of the 200th anniversary of
Pneumonia adults began in 1977, and in children in 2000, resulting in a similar decline. Due to the relatively low awareness of the disease, 12 November was declared as the annual World Pneumonia Day, a day for concerned citizens and policy makers to take action against the disease, in 2009. The global economic cost of community-acquired pneumonia has been estimated at $17 billion annually. Other estimates are considerably higher. In 2012 the estimated aggregate costs of treating pneumonia in the United States were $20 billion; the median cost of a single pneumonia-related hospitalization is over $15,000. According to data released by