1. Department of Pathology, The Johns Hopkins University School of Medicine,1 and
2. Department of Pathology, The University of Maryland School of Medicine,2 Baltimore, Maryland;
3. Section of Infectious Diseases, Saint Mary's Duluth Clinic Health System, Duluth, Minnesota3;
4. Department of Medicine and Epidemiology, Veterinary Medical School, University of California, Davis, California4; and
5. Department of Pathology, The University of Texas Medical Branch, Galveston, Texas5