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
Epidemiology of pneumonia case fatality rate in the UK is around 5–10%. In the United States, community-acquired pneumonia affects 5.6 million people per year, and ranks 6th among leading causes of death. In 2009, there were approximately 1.86 million emergency department encounters for pneumonia in the United States. In 2011, pneumonia was the second-most common reason for hospitalization in the U.S., with approximately 1.1 million stays—a rate of 36 stays per 10,000 population. Pneumonia was one of the top ten most expensive conditions seen during inpatient hospitalizations in the U.S. in 2011, with an aggregate cost of nearly $10.6 billion for 1.1 million