1. Ruminant Diseases and Immunology Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, Ames, Iowa, USA
2. Department of Avian Diseases, Kimron Veterinary Institute, Beit Dagan, Israel
3. Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
4. Infectious Bacterial Diseases Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, Ames, Iowa, USA
5. Department of Infectious Diseases and Pathobiology, Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland