Zika Virus Does Cause Birth Defects

Scientists confirm what many suspected, but questions remain.
Photographer: Dado Galdieri/Bloomberg
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After months of mounting evidence, scientists are ready to say definitively that the mosquito-borne Zika virus spreading across the Americas is causing birth defects, a link that the head of the Centers for Disease Control called “unprecedented.”

“There is no longer any doubt that Zika causes microcephaly,” CDC Director Tom Frieden declared Wednesday. A spike in microcephaly, when babies are born with abnormally small heads, raised the level of alarm about the disease in Brazil last year. “Never before in history has there been a situation where a bite from a mosquito could result in a devastating malformation.”