The four counties are Miami-Dade, Hillsborough, Lee and Santa Rosa.
There have been nine people in total who have been diagnosed with the Zika virus in Florida, though health officials believe that all of them contracted the disease while outside of the U.S.
Scott said he wanted the state to be prepared for the chance that the virus could start to be spread from mosquito to person within the state. The Aedes aegypti mosquito that is the primary vector of Zika virus infections is present in the southeast portion of the country, including Florida, though in winter the mosquito populations are low.
There have been no reports of the virus is being transmitted from mosquitoes to people in the U.S., though officials are concerned that small outbreaks could happen as the weather warms. A rare case of sexually transmitted Zika virus was reported in Dallas on Tuesday by the local health department.
Scott's executive order requires the state health officer to "take any action necessary to protect public health" and allows the commissioner of agriculture to issue a "mosquito declaration" in the affected counties to reduce populations of the insects that can spread the disease.