An outbreak of legionellosis linked to bath water circulating through a filter at a spa resort, March-April 2000 - Shizuoka
(IASR 2000; 21: 188-188)

In the end of March 2000, several hospitals in the western region of Shizuoka Prefecture sent specimens of pneumonia patients suspected of legionellosis. Four patients were confirmed as legionellosis by sputum and bronchoalveolar lavage (BAL) culture and soluble antigen detection from urine using enzyme-linked immunosorbent assay (ELISA). Because all of them had episodes of visiting spa S at a recreational facility in Kakegawa City, the local health center was advised to investigate the facility immediately. Of 14 water samples collected, 2 samples, which belonged to the same water system yielded Legionella pneumophila serogroup 1 (outdoor bubble bath water; 57,000 CFU/dl, indoor bathtub water 88,000 CFU/dl). Those isolates were turned out to be identical with those of the patients by pulsed-field gel electrophoresis (PFGE) and RAPD.

Further investigation revealed that 21 males and 2 females aged between 50-86 developed either legionella pneumonia or upper respiratory infection and 2 died. The incidences occurred during March 2 to April 4, and those cases bathed from the end of February to March 29. Incubation period varied from 1 to 10 days. Facility S opened in February, 2000, and some 57,000 individuals utilized the facility until it was closed on April 1. The facility piped sodium-based spa water to 27 baths, and the water was circulated through 5 sand-filtration tanks with chloride. The spa water was changed once in a week. The water system inspection found that the chloride supplier had not worked sufficiently, and this malfunction caused the growth of Legionella bacteria.

Reported by: Kanji Sugiyama, Tomohiro Nishio, Yoshiaki Goda, Kyoko Masuda, Zhang Fanfei, Masato Akiyama and Hideki Miyamoto; Shizuoka Institute of Environment and Hygiene

Correspondence: Kanji Sugiyama;
E-mail: kaneibio@hq.pref.shizuoka.jp
Fax: +81-54-245-7636

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