Zika virus goes undetected for year before first case diagnosed

New research suggests the Zika virus spread for a year before the first infections were reported.A new analysis from MIT and Harvard scientists suggests Zika was spreading in Brazil in February 2014.Researchers at Florida Gulf Coast University report a similar situation in the U.S.They say local transmission of Zika started in Florida months before the first case was confirmed.Researchers say it was not a single case that introduced the virus, but instead, at least four separate transmissions.