Miami (AFP) - Five new cases of Zika have been found in the tourist hotspot of Miami Beach, signaling the spread of local transmission of a virus blamed for birth defects, officials said Friday.
Pregnant women and those who want to become pregnant are urged to stay away from two areas -- a 1.5 square mile (3.9 square kilometer) section of Miami Beach and a neighborhood north of downtown called Wynwood -- where mosquitoes are actively spreading the disease, the US Centers for Disease Control and Prevention said.
Zika is spread by mosquitoes and sexual contact. Women who want to get pregnant, along with their partners, are urged to use mosquito spray and condoms or avoid sex altogether.
While the formal travel advisory for pregnant women is limited to two active transmission zones, pregnant women and their partners "may also consider postponing non-essential travel to all parts of Miami-Dade County," CDC chief Tom Frieden told reporters.
Throughout Miami-Dade County, a vast area with two million residents and 20,000 pregnant women, "there is the possibility that there could be transmission that hasn't yet been identified," Frieden said during a conference call.
The five cases in Miami Beach involve two local residents and three tourists -- hailing from New York, Texas and Taiwan -- Florida Governor Rick Scott told a news conference.
Florida now has 36 cases of locally transmitted Zika virus, according to the state department of health.
The state has a total of 524 cases of Zika, most of them brought in by people who were infected while traveling to areas of Latin America where the virus is spreading.
- Warnings to avoid travel -
Florida officials have faced questions about why it took so long to announce the new Zika transmission zone, with some critics accusing the governor of delaying the announcement to avoid scaring off visitors crucial to the state's lucrative tourism industry.
The CDC said the first Miami Beach case was identified in late July.
The health authority counts two weeks back to establish the at-risk period, to allow for the virus's two-week incubation period, Frieden explained.
Therefore, anyone concerned about Zika who traveled to Miami Beach from July 14 onward should seek medical advice and testing, he said.
Scott announced the Zika active transmission zone in Miami Beach on August 19, a day after media reports quoting unnamed health officials said a cluster of Zika cases had been identified there.
Asked by a reporter about the speed of Scott's announcement, Frieden praised Florida's "aggressive" actions, saying the process of identifying and tracing local spread of Zika is "complex."
"Florida is following the CDC recommendation for defining a risk area," he said.
Zika causes only mild symptoms for most people. But in pregnant women, it can cause microcephaly, a deformation in which babies are born with abnormally small brains and heads.
Zika has also been linked to a potentially fatal disorder known as Guillain-Barre syndrome, which can lead to nervous system problems such as weakness and paralysis.
So far, Florida is the only state in the mainland US where it has been reported.
The first local case, located in a one-square-mile zone north of downtown Miami called Wynwood, was announced on July 29.
More than two dozen people are believed to have been infected since then by mosquitoes carrying the virus in Wynwood.
- Concerns in Miami Beach -
The spread of Zika in the Miami area has raised concern that visitors may avoid the popular tourist resort.
Miami Mayor Tomas Regalado told AFP on Friday that 15 public events in Wynwood had been cancelled in the past 10 days and cancellations were running through September and October.
Among them was a circus brought in by a brewery, he said.
"The biggest worry is Art Basel, which means a lot of money," the mayor said of the international art show in Miami that is scheduled in early December and saw 77,000 visitors last year.
"People eat in high-end restaurants, stay in high-end hotels."
The governor on Thursday called on state business and health associations to work with the tourism industry on Zika prevention and education.
He also called on the state health department to offer mosquito spraying to hotels, restaurants and attractions in Miami-Dade County at no cost.