1. Microbiology Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi 329-0412, Japan
2. Research Planning and Coordination Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi 329-0412, Japan
3. Racehorse Clinic, Ritto Training Center, Japan Racing Association, Ritto, Shiga 520-3085, Japan