Detailed maps published in the journal eLife show that more than two billion people live in parts of the world where the Zika virus can spread.
Last week the US Centers for Disease Control and Prevention confirmed that the virus causes severe birth defects.
The at-risk zones in South America include long stretches of coastline as well as cities along the Amazon River and its tributaries snaking through the continent.
And in the US, Florida and Texas could sustain the infection when temperatures rise in summer.
Both Africa and Asia have large areas that could be susceptible to the virus, the researchers said.