FLORIDA-- New research suggests Zika began spreading in Florida mosquitoes about three months before infections were detected in the Miami area last summer.
The researchers also found the virus likely was carried in by travelers from the Caribbean.
They say mosquitoes started picking up the virus from infected travelers as early as March. It wasn't until July that Florida health officials said they had detected a local infection - the first in the U.S. mainland.
The research comes from scientists who examined genetic information from people and mosquitoes. The findings were released Wednesday in the journal Nature.
Most people infected with Zika don't get sick. It can cause a mild illness, with fever, rash and joint pain. But infection during pregnancy can lead to severe brain-related birth defects in babies
