Legionnaires' disease

Legionnaires' disease, severe lung infection. Legionnaires' disease appeared in 1976 when 182 delegates attending an annual convention of the American Legion in Philadelphia contracted a severe respiratory infection. Of 147 of those hospitalized, 90% developed pneumonia and 29 died. All had stayed in, or visited, the same hotel during the 4-day convention. Five months later, the organism responsible, a small Gram-negative, non-acid-fast bacillus, was isolated from the lung tissues of 4 fatal cases, and was subsequently named Legionella pneumophila. It is now clear that the organism is a significant respiratory pathogen, in both the United States and Western Europe.

After an incubation period of 2 to 10 days, the illness begins with symptoms of malaise, headache, and muscular aches and pains, succeeded in a few hours by high fever and shivering. A dry cough, or a cough producing small amounts of bloodstained sputum, begins on the second or third day, with pleurisy (inflammation of the pleura, the membrane covering the lungs) a common occurrence. Watery diarrhea with abdominal distention, occurring in around 50% of the sufferers, may precede the onset of fever. The antibiotic erythromycin is the most effective treatment for the disease.