1. Laboratory of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan
2. Laboratory of Veterinary Anatomy, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan
3. Laboratory of Veterinary Public Health, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan
4. Laboratory of Microbiology, Kitasato University School of Pharmacy, Minato, Tokyo 108-8041, Japan