1. Division of Infectious Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Ibaraki, Japan
2. Gunma Livestock Health Laboratory, Gunma, Japan
3. Shizuoka Prefectural Chubu Livestock Hygienic Service Center, Shizuoka, Japan
4. The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan