Health officials believe none of the cases originated in Florida. All involve people who contracted the disease while traveling to affected countries, they say.
Scott signed the order to cover Miami-Dade, Lee, Hillsborough and Santa Rosa counties. That's where all of the cases were detected.
The order allows the state's agriculture department to use mosquito spray more in those areas. It also directs the Florida Department of Health to make its own decisions about what's needed from the state and the Centers for Disease Control and Prevention.
The Zika virus, which is linked to a birth defect that causes brain deformities, primarily spreads through mosquito bites and rarely causes a severe illness in adults.
U.S. health officials say a person in Texas became infected with Zika through sex, in the first case of the illness being transmitted within the United States.
More than 5 million international visitors came to Central Florida in 2014, officials say, with 1.9 million of them from South America, primarily Brazil, where the virus is widespread.