1. Kagoshima University Veterinary Teaching Hospital, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
2. Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
3. Department of Veterinary Pathobiology, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan