1. Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
2. Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
3. Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, USA
4. University of Plymouth and The Vaccine Group Ltd, Plymouth, Devon, UK