1. Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., Baton Rouge, Louisiana 70803
2. Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, 903 South 4th St., Hamilton, Montana 59840
3. Department of Biomedical and Pharmaceutical Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana 59801
4. Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 2610