1. 1 Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA, 2 Laboratory of Hepatitis and Related Emerging Agents, Division of Emerging and Transfusion-Transmitted Diseases, Food and Drug Administration, Bethesda, MD 20892, USA, 3 Departments of Epidemiology and Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 2759