1. Yamaguchi Chubu Livestock Hygiene Service Center, 671-5 Kagawa, Yamaguchi 754–0897, Japan
2. Laboratory of Veterinary Pathology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677–1 Yoshida, Yamaguchi 753–8515, Japan
3. Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677–1 Yoshida, Yamaguchi 753–8515, Japan
4. Laboratory of Veterinary Microbiology, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan
5. School of Veterinary Medicine Department of Veterinary Medicine, Rakuno Gakuen University, 583 Bunkyodai Midorimachi, Ebetsu, Hokkaido 069–8501 Japan
6. Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3–8–1 Harumi-cho, Fuchu, Tokyo 183–0057, Japan