1. Laboratory of Small Animal Internal Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1–21–24 Korimoto, Kagoshima 890–0065, Japan
2. The United Graduate School of Veterinary Science, Yamaguchi University, 1677–1 Yoshida, Yamaguchi 753–8511, Japan
3. Merial Japan Ltd., 3–20–2 Nishi-shinjuku, Shinjuku-ku, Tokyo 163–1488, Japan