The CDC is working with Florida health officials to investigate what could be the first Zika infection from a mosquito in the continental United States.
They say lab tests confirm a person in the Miami area is infected with the Zika virus, and there may not be any connection to someone travelling outside the country.
The US Centers for Disease Control and Prevention says none of the more than 1300 Zika infections in the United States to date were from local mosquitoes. Fourteen were sexually transmitted and one involved laboratory exposure.
Mosquito control inspectors were at work in Miami-Dade County on Wednesday.
Spokeswoman Gayle Love said they've been going door-to-door since health authorities alerted them late last week, spraying to kill mosquitoes and emptying any containers holding water.
