How does Zika virus affect the brain during development?

Answer: Zika virus infection can cause microcephaly (an abnormally small and underdeveloped brain) in newborns.

mosquito zika virus brain development

Zika virus is a disease transmitted by mosquitoes. It was first identified in Uganda in 1947, but as recently as of 2015, outbreaks have been frequent among tropical and subtropical countries. It is estimated that more than 2 billion people are now at risk of becoming infected with Zika (Mapping global environmental suitability for Zika virus).

Zika symptoms are generally mild, but the virus itself can cross the placenta. There, it is known to destroy the neural stem cells of the developing child. It does so by interacting with the AXL protein, which is expressed on the end feet of radial glial cells. These cells are essential for the correct targeting of stem cells during for formation of the cerebral cortex.

The loss of these stem cells leads to a malformation of cortical development. This leads to a severe congenital birth defect called microcephaly that is observed in the newborns. In patients with microcephaly, they are born with an abnormally small head in proportion to the rest of their body.