1. Center for Comparative Medicine, University of California-Davis, Davis, CA 95616, USA
2. Department of Medical Microbiology and Immunology, University of California-Davis, Davis, CA 95616, USA
3. Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
4. California National Primate Research Center, University of California-Davis, Davis, CA 95616, USA
5. Department of Medical Pathology, University of California-Davis, Davis, CA 95616, USA