Florida officials on Tuesday announced the first case of Zika transmitted by mosquitoes in Pinellas County, located some 265 miles (425 km) from Miami, where the first locally transmitted U.S. cases were reported.
Steve Huard, acting spokesman for Florida Department of Health in Pinellas County, said the case involves a woman without a significant travel history, indicating the virus was contracted locally.
He did not know the timeline on the case, only that it had been confirmed within the past day. He did not have any more details on the patient's illness.
"At this point, it's a single case. It's a one off," Huard said. "We don't know where it originated, and we are doing appropriate testing and medical surveillance."
Florida Governor Rick Scott said the state department of health has begun door-to-door outreach in Pinellas County, testing individuals to find other cases.
Pinellas County is home to St. Petersburg, Clearwater and a number of Gulf Coast beaches that are popular tourist destinations.
A Miami-Dade County mosquito control worker sprays around a home in the Wynwood area of Miami, Aug. 1, 2016.
Scott said the health department and Pinellas County Mosquito Control have begun "aggressive spraying and mosquito abatement efforts," and he said any pregnant woman who wants a free Zika test or a Zika prevention kit should contact the health department.
The Zika virus was first detected in Brazil last year and has since spread across the Americas. The virus poses a risk to pregnant women because it can cause severe birth defects. It has been linked to more than 1,800 cases of microcephaly in Brazil.
Federal health officials on Friday warned pregnant women not to travel to Miami Beach after Florida confirmed that the mosquito-borne Zika virus was active in the popular tourist destination, becoming the second area in Miami to be affected after Wynwood.
Mara Gambineri, a spokeswoman for the Florida Department of Health said the department believes ongoing local transmission is only occurring in the small areas identified in Miami-Dade County.
On Tuesday, Florida also announced four new cases of Zika in the Wynwood neighborhood, where officials have been aggressively spraying for the mosquitoes that carry the virus for weeks.
Gambineri said in an email the cases of individuals in Wynwood experienced Zika symptoms in mid-July, prior to the start of an aerial spraying campaign.
Gambineri said the cases were only announced today because the individuals required antibody testing to rule out other mosquito-borne illness, such as dengue and Chikungunya.
Dr. Amesh Adalja, an infectious diseases expert at the University of Pittsburgh Medical Center, said Florida needs to make it clear that "anywhere these mosquitoes are present is at risk."
Adalja said while knowing the exact area of transmission is important for issuing travel warnings to pregnant women, he said the entire state needs to be vigilant.
Adalja expects multiple counties in Florida will be affected, as well as areas in Texas and Louisiana, though these outbreaks will be limited to discreet areas.