An outbreak of Legionnaires' disease in Sweden: report of sixty-eight cases.

From August 27 to September 21, 1979, 58 patients fell ill with Legionnaires' disease (LD) in the town Västerås, Sweden. All patients had been staying in the town some time during 2 weeks preceding their illness, as had 10 LD patients who fell ill from mid-June to mid-August the same year. Clinically, high fever, headache, dizziness and gastrointestinal symptoms were dominating. Respiratory symptoms were moderate, radiologically verified pneumonia was seen in 59 of 64 patients examined. One patient died. The diagnosis was verified by serology, using the IFL method, in all cases. Legionella pneumophila serogroup 1 was isolated from a closed lung biopsy from 3 patients. Isolates of identical strains were made from the cooling tower on the roof of an indoor shopping centre in Västerås, visited by 57 of the patients during the incubation period.