1. Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.
2. Department of Veterinary Pathobiology and Preventive Medicine, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.
3. College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766, USA.