1. Laboratory of Food Hygiene, Department of Food and Life Sciences, The Graduate School of Life and Environmental Sciences, Azabu University, Sagamihara, 252-5201, Japan
2. Laboratory of Parasitology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753-8515, Japan
3. Division of Microbiology, National Institute of Health Sciences, Setagaya, 158-8501, Japan