Infection of several IFN deficient mouse models with various ZIKV strains has demonstrated that placental insufficiency and fetal demise occurred during early gestation (embryonic day 6, E6) whereas infection during mid-gestation (E9) produced reduced cranial dimensions, and infection later in pregnancy (E12) resulted in no fetal disease (15, 30–32). The gene discussed is IFNA1; the disease is infection.