1. Aichi Prefectural Chuo Livestock Hygiene Service Center, 1-306 Jizono, Miaicho, Okazaki, Aichi 444-0805, Japan
2. Bacterial and Parasitic Disease Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
3. Pathology and Pathophysiology Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
4. Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-oraikita, Izumisano, Osaka 598-8531, Japan