1. Hokkaido Hiyama Livestock Hygiene Service Center, 281-1 Tazawamachi, Esashi, Hiyamagun, Hokkaido 043-0023, Japan
2. Bacterial and Parasitic Disease Research Division, National Institute of Animal Health, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan