Credit: Akiko Iwasaki & Laura Yockey/Yale/Howard Hughes Medical Institute
In a thick membrane that lines the uterus during pregnancy, cells infected with Zika (purple) secrete type I interferons (blue stars). Fetuses that lack protein receptors that bind interferons continue to develop (IFNAR-/- fetus, left). In contrast, fetuses with the receptors are disturbed by type I interferons, which disrupt the development of the placenta and lead to abnormal blood vessel growth, hypoxia, and fetal death (IFNAR +/-, right).