1. Laboratory of Veterinary Anatomy, Department of Basic Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan
2. United Graduate School of Veterinary Medicine, Gifu University, Gifu 501-1193, Japan
3. Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido 060-0818, Japan
4. Institute of Cetacean Research, Tokyo 104-0055, Japan
5. Department of Life Science and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan
6. Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan
7. Faculty of Veterinary Medicine, Gadjah Mada University, Yogyakarta 55281, Indonesia