1. Division of Biomedical Food Research, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo 158-8501, Japan;
2. Shimane Prefectural Meat Inspection Centre, Asayama-cho senzan 1677-2, Ota, Shimane 699-2212, Japan;
3. Department of Infectious Diseases, Hokkaido Institute of Public Health, Kita19 Nishi 12, Kita-ku Sapporo, Hokkaido 060-0819, Japan;
4. Department of Animal Nursing Science, Yamazaki Gakuen University, Minami-Osawa 4-7-2, Hachioji 192-0364, Japan;
5. Department of Veterinary Public Health, Nihon University, Kameino 1866, Fujisawa, Kanagawa 252-0880, Japan;
6. Department of Parasitology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan;
7. Department of Microbiology, Tokyo University of Agriculture, Sakuragaoka 1-1, Setagaya-ku, Tokyo 156-8502, Japan; and
8. Department of Animal Hygiene, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan