Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America.|Department of Biological Statistics & Computational Biology, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America.|Department of Biological Statistics & Computational Biology, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America.|Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.|Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America.