More than 1,600 babies were born in Brazil with microcephaly, or abnormally small heads, from September 2015 through April 2016 due to Zika virus. The epidemic took health professionals by surprise because the virus had been known since 1947 and had not been linked to birth defects.

Does Zika still cause microcephaly?

Zika virus causes a viral disease transmitted to humans mainly by the infected Aedes mosquito bite. The infection is not severe in most cases; however, there is evidence that infection during pregnancy may be associated with fetal genetic abnormalities (including microcephaly).

Why does the Zika virus cause microcephaly?

By preferentially destroying radial glial cells, Zika virus can produce severe microcephaly. Evolutionary changes such as mutations or recombination events might be responsible for the increased virulence and a new spectrum of Zika disease. Recombination events were reported to occur in different Zika viral strains.