1. Department of Microbiology, Faculty of Science,1 and
2. Center for Southeast Asian Studies, Kyoto University, Yoshida, Sakyo-ku, Kyoto,2 and
3. Department of Pathology, Faculty of Medicine,3 Prince of Songkla University, Hat-yai, Thailand, and
4. Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka,4 Japan