1. School of Veterinary Medicine University of California Davis California USA
2. College of Veterinary Medicine North Carolina State University Raleigh North Carolina USA
3. College of Veterinary Medicine University of Georgia Athens Georgia USA
4. College of Agriculture, Food and Environment, Maxwell H. Gluck Equine Research Center University of Kentucky Lexington Kentucky USA
5. Institut für Virologie, Freie Universität Berlin Berlin Germany
6. College of Veterinary Medicine Michigan State University, Veterinary Medical Center East Lansing Michigan USA
7. School of Veterinary Science University of Liverpool, Leahurst Campus Neston UK