1. National Research Institute for Veterinary Virology and Microbiology, Russian Academy of Agriculture Science, Pokrov, Russia
2. Department of Pathobiology and Veterinary Science and Center of Excellence for Vaccine Research, University of Connecticut, Storrs, CT, USA
3. School of Veterinary Medicine & Biomedical Sciences and Nebraska Center for Virology, University of Nebraska, Lincoln, NE, USA
4. Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA