1. Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
2. Division of Biosafety Control and Research, National Institute of Infectious Diseases, Tokyo, Japan
3. Department of Wildlife Science, School of Veterinary Medicine, Kitasato University, Aomori, Japan
4. Department of Veterinary Pathology, School of Veterinary Medicine, Kitasato University, Aomori, Japan
5. Department of Microbiology, School of Veterinary Medicine, Kitasato University, Aomori, Japan
6. Department of Microbiology, Faculty of Veterinary Medicine, Okayama University of Science, Ehime, Japan