Statistical analysis
VIRUS
R version 3.3.3 was used to perform statistical analyses. Two-way mixed ANOVA was used to compare the mean differences (temperature, weight, virus loads, etc.) between groups that were divided into two “factors” (independent variables), one of which is a “within-subjects” factor (time) and the other is a “between-subjects” factor (treatment or control). For anal swabs, there is only one none-zero data points in the treatment group. Therefore, the ANOVA method relying on variance could not be used, and Mann-Whitney U test was used instead. For viral loads in tissues, 