1. Kagoshima Central Livestock Hygiene Service Center, 1678 Yuda, Kagoshima 899–2201, Japan
2. Kyushu Research Station, National Institute of Animal Health, NARO, 2702 Chuzan, Kagoshima 891–0105, Japan
3. Viral Disease and Epidemiological Research Division, National Institute of Animal Health, NARO, Tsukuba, Ibaraki 305–0856, Japan