1. California Regional Primate Research Center and Department of Pathology, School of Medicine, University of California-Davis, Davis, California 95616.
2. California Regional Primate Research Center and Department of Pathology, School of Medicine, University of California-Davis, Davis, California 95616; Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California-Davis, Davis, California 95616 and Center for Comparative Medicine, University of California-Davis, Davis, California 95616.