I514 results in increased monocyte recruitment early in infection and preferentially infects lymphoid tissue within the gut, leading to extraintestinal spread via the blood.

(A,B)Stat1^-/- mice were inoculated orally with 10⁶ PFU of the indicated viral strains or vehicle control. At 2 dpi, mice were sacrificed and single-cell suspensions of the MLNs and Peyer’s patches (PP) were analyzed by flow cytometry for relative percentages of monocytes (A) and infected monocytes (B), with gating performed as shown in S7 Fig. N = 3–10 mice per group from two-five independent experiments. Data were analyzed by Kruskal-Wallis test followed by Dunn’s multiple comparisons test using naïve mice as a comparator. (C) WT mice were inoculated orally with 10⁶ PFU of the indicated viral strains and sacrificed at 1 dpi. Ileum, colon, and Peyer’s patches were harvested and MNoV genome copies were quantified via qPCR. N = 8–9 mice per group from two independent experiments. Groups were assessed for normality with the D’Agostino and Pearson test; tissues with normal distributions (Peyer’s patches and colon) were compared with Welch’s t-test, while tissues with non-normal distributions were compared with Mann-Whitney test. (D) WT and Stat1^-/- mice were inoculated orally with 10⁶ PFU of the indicated viral strains and blood was harvested at 5 dpi via submandibular bleed. RNA was extracted from whole blood, as well as separated cellular and serum blood fractions, and MNoV genome copies were quantified via qPCR. Groups were compared via a mixed-effect analysis with the Geisser-Greenhouse correction, followed by Tukey’s multiple comparisons test. N = 5–12 mice per group from at least two independent experiments. ***, P < 0.001; **, P < 0.01; *, P < 0.05; ns, not significant.