Florida is investigating a new case of Zika infection outside the neighborhood in Miami where mosquitoes are believed to have spread the virus to more than a dozen people, officials said Monday.

Florida Governor Rick Scott described the case as a "new individual with non-travel related Zika in Palm Beach County," north of Miami.

The person had recently traveled to Miami-Dade County and the Health Department is investigating "to determine the source of infection," Scott said in a statement.

The Florida Department of Health stressed that the investigation "does not mean active transmission of Zika is occurring in Palm Beach County," a statement said.

"If the department identifies any area of concern in Palm Beach County, we will notify the public immediately."

Zika can cause birth defects including a condition known as microcephaly, in which an infant's head is smaller than normal.

The US Centers for Disease Control and Prevention has warned pregnant women to stay away from the Miami neighborhood of Wynwood, where mosquitoes carrying the virus are believed to be lurking.

The state health authorities still maintain that "active transmissions are only taking place within the identified area that is less than one-square mile in Miami-Dade County," said the governor.

Since July, Florida has documented 17 cases of Zika that were likely acquired by mosquitoes carrying the virus inside the state.

There have also been 357 cases of Zika involving people who were infected while traveling outside the United States to areas where the virus is spreading, mainly in Latin America.

Florida is the first state in the mainland United States to report locally acquired Zika.