1. Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602
2. Istituto di Patologia Speciale e Clinica Medica Veterinaria
3. Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024
4. Department of Pathology, University of Washington, Seattle, Washington 98195
5. Istituto di Patologia Generale, Anatomia Patologica e Clinica Ostetrico-Chirurgica Veterinaria, Facoltà di Medicina Veterinaria, Università degli Studi di Sassari, 07100 Sassari, Italy
6. Moredun Research Institute, International Research Center, Penicuik, Midlothian EH26 0PZ, United Kingdom