Zika virus kills cells that form key brain tissue: report

In what may be the first lab evidence of the potency of the Zika virus, researchers in the United States have found that it severely damages a type of neural stem cell that gives rise to the brain’s cerebral cortex.

The findings are significant given that the World Health Organisation (WHO) is set to decide, within the next few months, whether the Zika virus — historically known to be relatively benign — is indeed wholly responsible for the outbreak of microcephaly, or deformed skulls, in newborns in Brazil and other parts of South America.

The team of researchers, led by Guo-li Ming and Hongjun Song of the Johns Hopkins University School of Medicine and Hengli Tang of Florida State University report in the current edition of the journal Cell Stem Cell that they saw the virus’ destruction, on neuronal cells derived from human induced pluripotent stem cells.

“This is a first step, and there’s a lot more that needs to be done,” said Mr. Song, a neuroscientist and stem cell biologist. “What we show is that the Zika virus infects neuronal cells in dish that are counterparts to those that form the cortex during human brain development. We still don’t know at all what is happening in the developing foetus. These findings may correlate with disrupted brain development, but direct evidence for a link between Zika virus and microcephaly is more likely to come from clinical studies,” the statement added.

Several other questions however remain. For instance, why are the symptoms in adults so mild? How is the virus entering the nervous system of the developing foetus?