Zika Virus RNA Replication and Persistence in Brain and Placental Tissue

This study examined placental tissues from 44 women and brain tissues from 8 deceased infants who had microcephaly. All samples were from patients suspected to be infected with Zika, and testing detected Zika virus in all infant tissues and nearly three-quarters of the placental tissues of women with adverse pregnancy or birth outcomes. Zika virus RNA was found in placentas and fetal brains more than seven months after pregnant women contracted Zika. Additionally, Zika RNA levels were 1,000 times higher in the brain than the placenta tissues.