CASP3 and infection: At 24 h post-infection (hpi), the blastocysts were stained with antibodies against CDX2 (trophectoderm)33, ZIKV E antigen, and Cleaved Caspase 3 (CAS3, cell apoptosis marker), and evaluated using confocal microscopy (Fig. 1b, Supplementary Movies 1–3).