1. Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan, Nakatsu Veterinary Surgery Hospital, Shorinji-cho nishi 2-2-15, Sakai 590-0960, Japan, Laboratory of Wildlife Biology, Department of Environmental Veterinary Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Kita18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan, and Ehime Prefectural Institute of Public Health and Environmental Science, Sanban-cho 8-234, Matsuyama 790-0003, Japan