1. Laboratory of Veterinary Public Health, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan.
2. Ohara Research Laboratory, Ohara General Hospital, Fukushima, Japan.
3. Kanagawa Prefecture Natural Environment Conservation, Atsugi, Kanagawa, Japan.
4. The United Graduate School of Veterinary Science, Gifu University, Gifu, Japan.
5. Department of Veterinary Science, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan.
6. Faculty of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan.
7. Laboratory of Medical Zoology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan.