Zika virus definitely causes microcephaly and other birth abnormalities, US CDC announces

The US Centres for Disease Control has announced there is no longer any doubt that the Zika virus causes microcephaly and other severe birth abnormalities, marking a turning point in an epidemic that has spread to nearly 40 countries and territories in the Americas and elsewhere.

Scientists at the CDC conducted a careful review of existing research and agreed that the evidence was conclusive, Director Thomas Frieden said. It is the first time a mosquito-borne virus has been linked to congenital brain defects.

“It is now clear, and CDC has concluded, that the virus causes microcephaly,” Frieden said. CDC is launching more studies to determine whether children with that rare condition, which is characterized at birth by an abnormally small head, represent the “tip of the iceberg of what we could see in damaging effects on the brain and other developmental problems.”

The outcome validates the growing research of past months that strongly implicated Zika as the culprit behind a broad set of complications in pregnancy. The pathogen is also increasingly linked to neurological problems in adults. The CDC report, published in the New England Journal of Medicine, focused only on reviewing the evidence linking Zika and fetal anomalies.

Global health officials had already assumed the virus was to blame for the problems being seen in various countries. Since January, many have advised women who were pregnant or hoping to become so to avoid travel to Zika-affected areas or to take steps to avoid Zika infection. That medical advice expanded over time to include women’s partners, especially as it became clear sexual transmission of the virus was more common than had been known.

The research released Wednesday won’t change that advice, officials said. But they are hoping it will help educate the public about the virus and its potential for harm.