We report a case of leptospirosis in Tokyo in winter due to a rat bite, an uncommon cause of Leptospira infection. In Japan, many cases due to exposure to fresh water have been reported from domestic southwest islands in summer. However, a previous report on leptospirosis in Tokyo documented several cases occurring in winter. The main route of infection in the Tokyo metropolitan area during winter was attributed to the increased chance of direct rat exposure. Rapid and feasible diagnostic methods are needed to elucidate its epidemiology and provide prompt treatment.
Financial support: K. Y. received research grants from Fujirebio, Inc., Mizuho Medy, Co., Ltd., and VisGene Inc., Sanyo Chemical Industries, Ltd., outside the submitted work.
Authors’ addresses: Tetsuya Suzuki, Shinichiro Morioka, Hidetoshi Nomoto, and Norio Ohmagari, Department of Infectious Diseases, Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan, and Emerging and Re-emerging Infectious Diseases, Graduate School of Medicine, Tohoku University, Sendai, Japan, E-mails: tesuzuki@hosp.ncgm.go.jp, shmorioka@hosp.ncgm.go.jp, hnomoto@hosp.ncgm.go.jp, and nohmagari@hosp.ncgm.go.jp. Tatsuya Kikuchi, Lubna Sato, Kei Yamamoto, and Kayoko Hayakawa, Department of Infectious Diseases, Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan, E-mails: tkikuchi@hosp.ncgm.go.jp, rsato@hosp.ncgm.go.jp, kyamamoto@hosp.ncgm.go.jp, and khayakawa@hosp.ncgm.go.jp. Nobuo Koizumi, Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan, E-mail: nkoizumi@niid.go.jp. Satoshi Kutsuna, Department of Infectious Diseases, Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan, and Department of Infection Control, Faculty of Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan, E-mail: kutsuna@hp-infect.med.osaka-u.ac.jp.