1. Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine and Life Science; Nippon Veterinary and Life Science University; 1-7-1, Kyonan-cho Musashino-shi Tokyo 180-8602
2. Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine; Chiang Mai University; Mae Hia, Muang Chiang Mai 50100 Thailand
3. Yamagata Prefectural Central Livestock Health and Sanitation Office; 736 Urushiyama Yamagata-shi 990-2161
4. National Institute of Animal Health; 3-1-5, Kannondai Tsukuba-shi Ibaraki 305-0856 Japan