1. Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC 27606 USA
2. North Carolina State University; Raleigh NC 27606 USA
3. Department of Pathology and Laboratory Medicine and Lineberger Comprehensive Cancer Center; University of North Carolina at Chapel Hill; Chapel Hill NC 27599-7525 USA
4. Port city Veterinary Referral Hospital; Portsmouth NH 03801 USA