1. Department of Veterinary Internal Medicine Graduate School of Agricultural and Life Sciences The University of Tokyo Tokyo Japan
2. Department of General Medicine IMSUT Hospital The Institute of Medical Science The University of Tokyo Tokyo Japan
3. Department of Infection Microbiology Research Institute for Microbial Diseases Osaka University Osaka Japan
4. Department of Infectious Diseases Control International Research Center for Infectious Diseases The Institute of Medical Science University of Tokyo Tokyo Japan
5. Department of Veterinary Pathology Graduate School of Agricultural and Life Sciences The University of Tokyo Tokyo Japan
6. Department of Gastroenterology Graduate School of Medicine Chiba University Chiba Japan