1. Microbiology Division, Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
2. Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
3. Epizootic Prevention Section, Equine Department, Japan Racing Association, 1-1-1 Nishi Shinnbashi, Minato-ku, Tokyo 105-0003, Japan