1. Biodiversity Division, Ecological Risk Assessment and Control Section, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan
2. Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Ibaraki, Japan
3. Avian Zoonosis Research Center, Faculty of Agriculture, Tottori University, Tottori 680-8553, Tottori, Japan
4. Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Hokkaido, Japan