1. The United Graduate School of Veterinary Sciences, Gifu University, Yanagito, Gifu 501–1193, Japan
2. Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183–8509, Japan
3. Kurayoshi Livestock Hygiene Service Center, Seidani, Kurayoshi, Tottori 682–0017, Japan
4. Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183–8509, Japan
5. Laboratory of Epizootiology, Department of Veterinary Medicine Faculty and Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183–8509, Japan
6. Laboratory of Microbiology, Department of Veterinary Medicine Faculty and Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183–8509, Japan