A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan

Corwin A (Division Surgeon's Office, 3rd Marine Division, FMFPAC, Okinawa, Japan), Ryan A, Bloys W, Thomas R, Deniega B and Watts D. A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan. International Journal of Epidemiology 1990; 19: 743-748.A waterborne outbreak of leptospirosis occurred among US military personnel during September 1987, on the island of Okinawa, Japan. Micro-agglutination titres for leptospiral antigen of ≥ 200 were detected in hospitalized adult males averaging 22.5 years of age with symptoms compatible with leptospirosis. Epidemiological findings revealed two case clusters distinguished by time and place of exposure. The overall attack rates among recreational swimmers and combat skills training participants were 467/1000 (7/15) and 183/1000 (15/82), respectively. Swallowing of water differentiated individuals with laboratory-confirmed infection from those with no infection, while water immersion alone did not appear to result in leptospiral infection. Additionally, subnormal rainfall may have contributed to the risk of exposure associated with this outbreak. © 1990 International Epidemiological Association.