In contrast to that observed in the diestrous phase after progesterone treatment, we did not detect differences in ZIKV infection of the vagina, cervix, uterus, serum, spleen, or brain in estradiol and progesterone-treated (proestrous phase) OVX WT and Ifnlr1−/− mice at 7 dpi in the absence of type I IFN signaling (Fig. 3a–d). Here, IFNLR1 is linked to Zika virus infectious disease.