Legionnaires' disease acquired its name in July 1976, when an outbreak of pneumonia occurred among people attending a convention of the American Legion at the Bellevue-Stratford Hotel in Philadelphia. Of the 182 reported cases, mostly men, 29 died. On January 18, 1977, the causative agent was identified as a previously unknown strain of bacteria, subsequently named "Legionella", and the species that caused the outbreak was named "Legionella pneumophila". Outbreaks of Legionnaires' disease receive significant media attention, but this disease usually occurs in single, isolated cases not associated with any recognized outbreak. When outbreaks do occur, they are usually in the summer and
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