1976 Philadelphia Legionnaires' disease outbreak States Center for Disease Control and Prevention (CDC) in 2017 only use the term Legionnaires' disease to refer to the serious version with pneumonia. CDC investigators quickly discovered outbreaks of respiratory disease caused by "L. pneumophila" dating back to 1959. An outbreak of what was dubbed Pontiac fever occurred in a health department in Pontiac, Michigan in July 1967. No one died. Although caused by the same bacterium, Pontiac fever is a milder ailment than Legionnaires' disease. Pneumonia is absent in those with Pontiac fever. An outbreak of pneumonia in July–August, 1965, at St. Elizabeths Hospital in Washington, DC, which
Legionella clemsonensis yellow. Legionella clemsonensis Legionella clemsonensis was isolated in 2006, but was discovered in 2016 by Clemson University researchers. It is a Gram-negative bacterium. “"Legionella"” is named after the American Legion convention where the first outbreak occurred, killing 34 people and sickening 221 individuals in 1976. It occurred in Philadelphia during the convention for the association of the U.S. veterans. The specific name "clemsonensis"” derives from Clemson University, where undergraduates DNA-sequenced this new strain. "Legionella" has a correlation with another genus called "Coxiella". Both cause lung infection that can eventually lead to pneumonia due to the intracellular bacteria in aerosols. Based