1. Department of Animal Hygiene, School of Veterinary Medicine and Animal Sciences, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628 Japan
2. Hikiiwa Park Center, Inaricho 1629, Tanabe, Wakayama, 646-0051, Japan
3. Laboratory of Veterinary Parasitology, Faculty of Agriculture, Yamaguchi University, Yamaguchi University, Yoshida 1677-1, Yamaguchi, Yamaguchi 753-8515, Japan
4. Laboratory of Veterinary Microbiology, Faculty of Agriculture, Yamaguchi University, Yamaguchi University, Yoshida 1677-1, Yamaguchi, Yamaguchi 753-8515, Japan