1. *Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802;
2. †Department of Microbiology and Immunology, MCP-Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, PA 19102;
3. ‡Departments of Agronomy and Statistics, Purdue University, West Lafayette, IN 47907;
4. §Department of Microbiology, Brigham Young University, Provo, UT 84602; and
5. ¶Neurovirology Research Laboratory, Veterans Affairs Medical Center, and Department of Neurology, University of Utah, Salt Lake City, UT 84148