1. Department of Clinical Studies, University of Pennsylvania, School of Veterinary Medicine, 3800 Spruce St, PA 19104, USA
2. Department of Clinical Diagnostic Services, North Carolina State University, College of Veterinary Medicine, 4700 Hillsborough St, Raleigh, NC 27606, USA
3. City of Angels Veterinary Specialty Center, 9599 Jefferson Blvd, CA 90232, USA
4. Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, 3800 Spruce St, PA 19104, USA