Mice deficient in IFN response genes, such as single knockout (Ifnar1) A129, double knockout (Ifnar1, Ifnar2) AG129, and triple knockout (Irf3, Irf5, Irf7) TKO mice16, succumb to ZIKV within a few days of infection making it difficult to investigate vertical transmission of ZIKV in such an aggressive disease model. Here, IRF5 is linked to infection.