Fig. 4

Histopathological examinations and villus/crypt ratio from the SFTSV-infected mice. Mice were inoculated i.p. with 5 × 10² FAID₅₀ SFTSV. The liver and small intestine of the C57 BL6 wild-type (WT), mice treated with blocking anti-type I interferon (IFN)-α receptor antibody (IFNAR Ab) were collected 1, 3, 7, and 12 dpi and the organs of the IFNAR knockout (IFNAR^−/−) mice were collected 1 and 3 dpi after infection. a The crosshatches and asterisks indicate coagulation necrosis and mononuclear cell infiltration in the liver, respectively. Bars 100 μm. b The WT mice had long, intact, regular villi at all time points, but the IFNAR Ab and IFNAR^−/− mice showed shortened, damaged, blunting villi, and the IFNAR Ab mice recovered at 12 dpi. Bars 200 μm. c At least 20 typical villi and crypts were measured for each mouse. The villus/crypt ratios are expressed as the mean ± standard deviation. Statistical analyses were performed using one-way ANOVA followed by Tukey’s multiple comparison test. *p < 0.05 and **p < 0.01 for 1 dpi vs. other dpi for the same group mice. #p < 0.05 for 3dpi vs. 12 dpi for the IFNAR AB mice