About 30 million people fly to the United States each
year from countries in the Caribbean and Latin America
that are currently affected by Zika. But experts say that
it is unlikely Zika would spread as quickly or as widely
in the United States, which has better mosquito control
and different environmental conditions.
Air travel has been a factor in the spread of Zika, which is circulating in about two dozen countries, according to Isaac I. Bogoch, author of a recent study on the spread of Zika in The Lancet. About 2.7 million people travel from Brazil to the United States each year. In 2014, Brazil had more than 1.6 million cases of dengue, a disease related to Zika that is spread by the same mosquitoes. But dengue outbreaks in the United States remain rare.