1. From the Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (T.J.L.), and the Division of Infectious Diseases, Johns Hopkins University, Baltimore (A.C.) — both in Maryland; the Toronto Centre for Liver Disease, Toronto General Hospital, University of Toronto, Toronto (J.J.F.); and the Laboratory of Virology and Infectious Disease, Rockefeller University, New York (C.M.R.).