Mechanisms of disrupted neurodevelopment after Zika virus infection in infancy.

Congenital and early-life Zika virus (ZIKV) infection can result in neurologic deficits. Precise mechanisms of injury, especially in the more subtle presentation of postnatal infection, are not fully elucidated. Here, we defined the effects of ZIKV on the developing brain using single cell transcriptomics, histopathology and design-based stereology, diffusion MRI, and neurobehavioral assessments in infant rhesus macaques. ZIKV upregulated interferon-stimulated genes in activated microglia and cell death pathways in neurons and downregulated metabolism and differentiation genes in mature oligodendrocytes. Abnormal micro-organization of the corpus collosum and limbic white matter tracts was seen on diffusion weighted imaging. A curated gene set associated with autism spectrum disorder risk was negatively enriched in inhibitory and excitatory neurons from ZIKV-infected infants, with increased emotional reactivity already evident two weeks following infection. From single cells to organism-level behaviors, these results define the pathways and processes disrupted by early-life ZIKV infection.