1. Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151–742, Republic of Korea
2. Dong Bang Co., Ltd., Dogok-Dong 517–8, Gangam-gu, Seoul 135–272, Republic of Korea
3. College of Oriental Medicine, Kyunghee University, 1 Hoegi-dong, Dongdaemun-Gu, Seoul 130–701, Republic of Korea
4. Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculty of Veterinary Medicine, University of Montreal, Quebec, Canada