A series of cases of Legionella pneumophila pneumonia, January-August 2000 - Yamagata
(IASR 2000; 21: 189-190)

In Yamagata Prefecture, only one legionellosis case had been reported in August 1996, however 8 cases were found during January to August 2000. Microbiological and epidemiological investigations were conducted.

Eight cases were all males aged over 40 years (40's 2 cases, 50's 2 cases, 60's 4 cases). All developed refractory pneumonia with high fever (>=39C), and 3 presented neurological disorders. The index case (January) and the second and third cases (April) had common episodes of bathing the same spa X in an inland town previously.

Sputum specimens were collected from 5 cases, but only one specimen yielded Legionella pneumophila serogroup 1. Of 8 cases, 6 urine specimens were Legionella antigen positive by enzyme-linked immunosorbent assay (ELISA). Those positive samples were collected during the 8th to 43rd ill day. One negative sample was collected at the 7th ill day, but it turned out to be positive when condensed 10 times. Another one sample remained negative, as it was collected after the 200th ill day. This case was diagnosed as legionellosis serologically.

Eighteen environmental samples were collected from 12 baths of spa X. High level contamination of L. pneumophila (1,000-10,000 CFU/dl) was observed in 4 baths, but the organism was not isolated from the other 8 baths. The isolates were classified as serogroup 1, 4, 5, 6, and UT. Sixteen serogroup 1 isolates collected from 3 baths and the case isolate were digested by SfiI, and tested for pulsed-field gel electrophoresis (PFGE). PFGE patterns of the environmental isolates were not matched with the case isolate. The case isolate was also compared with 10 serogroup 1 isolates, which had been collected from other spas, but they were not matched either.

Although the relationship of bathing at spa X and the development of legionellosis was not confirmed epidemiologically, the spa improved hygiene including the employment of chloride disinfection, quit of water fall bath and bubble bath where high level contamination of L. pneumophila was observed.

Reported by: Katsumi Ootani, Yumiko Sugahara, Masahide Sto, Shoko Murayama, Koichi Hayasaka; Yamagata Prefectural Institute of Public Health

Correspondence: Katsumi Ootani;
E-mail: kootani@eiken.yamagata.yamagata.jp

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