1. Division of Animal Life Science, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 3–5–8 Saiwai, Fuchu, Tokyo 183–8509, Japan
2. Department of Virology-I, National Institute of Infectious Diseases, 1–23–1 Toyama, Shinjuku, Tokyo 162–8640, Japan
3. Andoh Animal Hospital, 2259–13 Shitotonoya, Oyama, Tochigi 323–0827, Japan
4. Teramoto Animal Hospital, 1–61 Kakamigahara, Unuma, Kakamigahara, Gifu 509–0111, Japan
5. Kitasato Daiichisankyo Vaccine Co., Ltd., 6–111 Arai, Kitamoto, Saitama 364–0026, Japan
6. Ryukyu Animal Medical Center, Mizuhodai Animal Hospital, 5–27 Yone, Tomigusuku, Okinawa 901–0224, Japan
7. Department of Bacteriology-I, National Institute of Infectious Diseases, 1–23–1 Toyama, Shinjuku, Tokyo 162–8640, Japan