1. Laboratory of Veterinary Pathology; Tokyo University of Agriculture and Technology; 3-5-8 Saiwai-cho, Fuchu-shi Tokyo 183-8509 Japan
2. Chemicals Evaluation and Research Institute; Japan, 1-4-25 Koraku, Bunkyo-ku Tokyo 112-0004 Japan
3. Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences; Gifu University; 1-1 Yanagido, Gifu-shi Gifu 501-1193 Japan