Leptospirosis after recreational exposure to water in the Yaeyama islands, Japan

Abstract

Leptospirosis is a global zoonotic disease with a variety of clinical manifestations. We report an outbreak of leptospirosis in the Yaeyama Islands, Japan, in the summer of 1999 associated with heavy rainfall. Fourteen people were diagnosed with leptospirosis and required hospitalization. All cases were found to have exposure to contaminated soil or water. A history of recreational activities involving water sports was more frequent (71%) than occupational risk factors related to agriculture or construction (29%). Fever was the primary symptom in all cases, followed by chills (93%), headache (86%), myalgias (57%) and conjunctival suffusion (57%). All cases were successfully treated with antimicrobial therapy except one patient who improved spontaneously. Jarisch-Herxheimer reactions were seen in six cases (43%). The increasing incidence of leptospirosis related to recreational sports is an important public health problem in resort areas. A high-index of suspicion, early treatment, and prevention are crucial in this latently endemic area.

Figure 1

Relationship between rainfall and leptospirosis. Cases of leptospirosis were clustered from July to September 1999, several days (latent period) after unusually heavy rainfall. According to the Ishigakijima Local Meteorological Observatory, most of this excess precipitation occurred over a relatively short period of a few days.