1. Virus Research and Testing Group, Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, Daejeon, Korea.
2. Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, USA.
3. Department of Microbiology, Immunology and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, KY, USA.