Though mounting evidence suggests a link between Zika virus and microcephaly, the World Health Organization is urging that the connection is not scientifically proven and that new evidence in the coming weeks will help draw more absolute conclusions. New findings published in The Lancet Infectious Diseases do however suggest that the link is real.
Researchers examined amniotic fluid from two pregnant women in Brazil whose ultrasound scans suggested their infants had microcephaly. Last year in Brazil levels of microcephaly in infants were 20 times higher than in previous years, correlating with the appearance and rise of Zika virus. Of the two women, one presented Zika virus-like symptoms at 18 weeks into her pregnancy, the other at 10 weeks. The researchers detected the Zika virus genome in the amniotic fluid of both women, but not in their urine or serum, suggesting the ability of the virus to cross the placental barrier.
"This study cannot determine whether the Zika virus identified in these two cases was the cause of microcephaly in the babies," lead researcher Ana de Filippis, PhD, told the BBC. "Until we understand the biological mechanism linking Zika to microcephaly we cannot be certain that one causes the other, and further research is urgently needed."