Electron microscopy of the organism of Legionnaires' disease

Abstract

LEGIONNAIRES' disease, an acute lobar pneumonia with a considerable fatality rate, gained its name from the explosive outbreak which followed an American Legion convention in Philadelphia in July 1976 (ref. 1). Since then, some smaller outbreaks and an increasing number of sporadic cases have been recognised in the USA². There have also been reports of cases in the UK, from Glasgow, mainly associated with holiday travel^3,4, and, as an indigenous occurrence, from Nottingham^5,6 and London⁷. The causative organism, a small Gram-negative bacillus, has been cultured with some difficulty, its size being 0.3–0.5 µm in width and 2–3 µm in length, though longer forms up to 20 µm are not uncommon⁸. We present here electron micrographs showing the organism in post mortem lung tissue.