NEW YORK — Confirming the worst fears of many pregnant women in the United States and Latin America, US health officials said Wednesday there is no longer any doubt the Zika virus causes babies to be born with abnormally small heads and other severe brain defects.
Since last year, doctors in Brazil have been linking Zika infections in pregnant women to a rise in newborns with microcephaly, or an unusually small skull. Most outside experts were cautious about drawing such a connection. But now the US Centers for Disease Control and Prevention says enough evidence is in.
“There is no longer any doubt that Zika causes microcephaly,” CDC Director Dr. Tom Frieden said. The CDC said it also is clear Zika causes other serious defects, including damaging calcium buildups in the developing brain.
Among the evidence that clinched the case: signs of the Zika virus, which is spread primarily through mosquito bites and can also be transmitted through sex, have been found in the brain tissue, spinal fluid and amniotic fluid of microcephaly babies.
The CDC and other health agencies have been operating for months on the assumption that Zika causes brain defects, and they have been warning pregnant women to use mosquito repellent, cover up, avoid travel to Zika-stricken regions and either abstain from sex or rely on condoms. Those guidelines will not change.