1. Department of Virology II, National Institute of Infectious Diseases, Shinjuku-ku
2. Department of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, Minato-ku
3. Department of Pathology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo
4. Research Center for Emerging Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita-shi, Osaka
5. Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki-shi, Nagasaki, Japan