1. 1 Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
2. 2 Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
3. 3 Department of Pathobiology Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI