1. Laboratory of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori 034‑8628, Japan
2. Tohoku Women's College, Hirosaki, Aomori 036‑8503, Japan
3. Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036‑8562, Japan
4. Research and Development Department, Ichimaru Pharcos Co., Ltd., Motosu, Gifu 501‑0475, Japan