1. Division of Molecular Pathology, Department of Cellular Pathology, Armed Forces Institute of Pathology, Washington, D.C. 20306, USA
2. Department of Veterinary Pathology, Armed Forces Institute of Pathology, Washington, D.C. 20306, USA
3. Registry of Comparative Pathology, Armed Forces Institute of Pathology, Washington, D.C. 20306, USA
4. Department of Agriculture for Northern Ireland, Veterinary Sciences Division, Stoney Road, Stormont, Belfast, Northern Ireland