1. Graduate School of Infection Control Sciences Kitasato University 5-9-1 Shirokane Minato-ku Tokyo 108–8641 Japan
2. Ōmura Satoshi Memorial Institute Kitasato University 5-9-1 Shirokane Minato-ku Tokyo 108–8641 Japan
3. Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama University 1-1-1 Tsushima-naka, Kita-ku Okayama 700–8530 Japan