noun
also legionnaire's disease
Usage: usually capitalized L
Etymology: so called from its first recognized occurrence at a 1976 American Legion convention in Philadelphia
: pneumonia that is caused by a bacterium of the genus Legionella ( L. pneumophila ), that is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea, lobar pneumonia, and mental confusion, and that may be fatal especially in elderly and immunocompromised individuals