1. Division of Gastroenterology and Hepatology Department of Medicine Nihon University School of Medicine Tokyo Japan
2. Department of Quality Assurance and Radiological Protection National Institute of Infectious Diseases Tokyo Japan
3. Department of Virology II National Institute of Infectious Diseases Tokyo Japan
4. Division of Gastroenterology Tohoku University Graduate School of Medicine Sendai Japan
5. Division of Gastroenterology and Hepatology Graduate School of Medical and Dental Sciences Niigata University Niigata Japan
6. Department of Gastroenterology Graduate School of Medicine Chiba University Chiba Japan
7. Department of Emergency Medicine Oita University Yufu Oita Japan
8. Center for Experimental Medicine Jichi Medical University School of Medicine Shimotsuke Tochigi Japan
9. Division of Infectious Diseases Advanced Clinical Research Center Institute of Medical Science University of Tokyo Tokyo Japan
10. Department of Infectious Diseases and Applied Immunology Hospital of the Institute of Medical Science University of Tokyo Tokyo Japan
11. Division of Virology Department of Infection and Immunity Jichi Medical University School of Medicine Shimotsuke Tochigi Japan