1. Division of Transboundary Animal Diseases, Exotic Disease Research Station, National Institute of Animal Health, National Agriculture and Food Research Organization, Kodaira, Tokyo 187-0022, Japan
2. Division of Pathology and Pathophysiology, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-0856, Japan
3. Laboratory Department, Animal Quarantine Service, Ministry of Agriculture, Forestry and Fisheries, Yokohama, Kanagawa 235-0008, Japan
4. Yamagata Prefectural Chuo Livestock Hygiene Service Center, Yamagata, Yamagata 990-2171, Japan
5. Saitama Prefectural Chuo Livestock Hygiene Service Center, Saitama, Saitama 331-0821, Japan
6. Osaka Livestock Hygiene Service Center, Izumisano, Osaka 598-0048, Japan