Experimental transmission of legionnaires' disease by exposure to aerosols of Legionella pneumophila.

Pyrexia and pneumonia developed in guinea-pigs after exposure to aerosols of Legionella pneumophila in a Henderson apparatus. Mortality was high 1-3 days after exposure. Histopathological changes were of an acute fibrinopurulent pneumonia, with widespread fibrin exudation and accumulation of neutrophils and macrophages in alveoli-lesions similar to those of legionella pneumonia in man. Rhesus monkeys given low doses of bacteria had slight fever and mild histological lesions in the lungs. Aerosol infection of these species offers suitable experimental models of legionnaires' disease.