Kaplan-Meier survival plots and all statistical evaluations were done using Prism (GraphPad Software, CA). The log-rank test was used for survival analysis. For analyzing differences in viral titers, ALT levels, and weight change, a one-way analysis of variance (ANOVA) with Newman-Keuls post test or the Kruskal-Wallis (two-tailed) test with the Dunn's post test was performed based on Gaussian distribution of the data.