In 2015, Zika virus swept through Brazil and the Americas. It was the first time a mosquito-borne virus was known to cause severe birth defects, and the World Health Organization declared it a “public health emergency that warranted a global response.”

“This was a truly unprecedented phenomenon,” says Dr. Albert Ko, an epidemiologist at the Yale School of Public Health who has worked in Brazil for over two decades. “There was a new, emerging pathogen in the world.” The pandemic’s emergency status was lifted in November 2016. But it left more than 3,700 children born with birth defects — the most severe of which is microcephaly, where babies are born with small heads and brain damage — in its aftermath.

Read more at NPR…