A number of mouse ZIKV models have used IFNAR−/− mice (17), and ZIKVNatal (103 CCID50 s.c.)produced a 4- to 5-day viremia in IFNAR−/− mice that was ~1 to 4 logs lower than that produced by infection with the same dose of ZIKVMR766 (Fig. 2A). This evidence concerns the gene IFNAR1 and infection.