1. Department of Medical Entomology, National Institute of Infectious Diseases , Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640 , Japan
2. Department of Bacteriology II, National Institute of Infectious Diseases , Gakuen 4-7-1, Musashi-Murayama, Tokyo 208-0011 , Japan
3. Department of Bacteriology, Drug Resistance and Pathogenesis, Nagoya University Graduate School of Medicine , 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 , Japan