1976 Philadelphia Legionnaires' disease outbreak failed. The disease was finally produced in guinea pigs. The CDC announced the discovery at a press conference on January 18, 1977. The bacterium was later named "Legionella pneumophila". "Legionella pneumophila" is the most common cause, but sometimes other species of Legionella bacteria also cause Legionnaires' disease. The terms "Philadelphia fever" and "Legion fever" appear to have been used at the time of the outbreak and for shortly thereafter, although at least one 2008 source which covers disease in a historical narrative sense also included "Legion Fever" as alternate name. Both the World Health Organization in 2018 and the United
1976 Philadelphia Legionnaires' disease outbreak testing specimens. While the Center for Disease Control responded rapidly, as did the Pennsylvania Health Department, it took six months for the CDC microbiologist Joseph McDade to discover the cause of the outbreak. He initially thought the cause was viral because blood and tissues from the victims failed to grow bacteria when incubated in culture medium. His subsequent attempts to isolate the viral agent in eggs included antibiotics to kill off "contaminating" bacteria. It was only when he omitted the antibiotics that the bacteria grew in eggs. Attempts to reproduce the disease in mice, the standard laboratory animal model, also