Legionnaires' disease that occur globally is not known. Legionnaires' disease is the cause of an estimated 2-9% of pneumonia cases that are acquired outside of hospital. An estimated 8,000 to 18,000 cases a year in the United States require hospitalization. Outbreaks of disease account for a minority of cases. While it can occur any time of the year, it is more common in the summer and fall. The disease is named after the outbreak where it was first identified, at a 1976 American Legion convention in Philadelphia. The length of time between exposure to the bacteria and the appearance of symptoms is
American Legion Veterans of the Korean War were approved for membership in The American Legion in 1950, and The American Legion Child Welfare Foundation was formed in 1954. On May 30, 1969, the Cabin John Bridge, which carried the Capital Beltway (I-495) across the Potomac River northwest of Washington, was officially renamed to the "American Legion Memorial Bridge" in a ceremony led by Lt. Gen. Lewis B. Hershey, director of the U.S. Selective Service System. In 1976, an outbreak of bacterial pneumonia occurred in a convention of The American Legion at the Bellevue Stratford Hotel in Philadelphia. This pneumonia killed 34 people