Explainer: Where Did Zika Virus Come From and Why Is It a Problem in Brazil?

Explainer: Where Did Zika Virus Come From and Why Is It a Problem in Brazil?
A health worker stands in the Sambadrome as he sprays insecticide to combat the Aedes aegypti mosquitoes that transmit the Zika virus, in Rio de Janeiro, Brazil, Tuesday, Jan. 26, 2016. AP Photo/Leo Correa
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From October 2015 to January 2016, there were almost 4,000 cases of babies born with microcephaly in Brazil. Before then, there were just 150 cases per year.

The suspected culprit is a mosquito-borne virus called Zika. Officials in Colombia, Ecuador, El Salvador and Jamaica have suggested that women delay becoming pregnant. And the Centers for Disease Control and Prevention has advised pregnant women to postpone travel to countries where Zika is active.

Countries and territories with active Zika virus transmission. <a href="http://www.cdc.gov/zika/geo/index.html" target="_blank">Centers for Disease Control and Prevention</a>
Countries and territories with active Zika virus transmission. Centers for Disease Control and Prevention
Amy Y. Vittor
Amy Y. Vittor
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