Florida Gov. Rick Scott confirmed Friday that the Zika virus is being spread locally by mosquitoes in Miami Beach, a development that marks an expansion of the outbreak in South Florida and immediately prompted a new travel advisory by federal officials.

"We believe we have a new area where local transmissions are occurring in Miami Beach,” Scott said at a noon press conference.

This area covers about 1.5 square miles between 8th and 28th streets and between the beach and Intracoastal Waterway -- a stretch that encompasses the vibrant, densely packed South Beach tourist district. It also encompasses the Miami Beach Convention Center, which is set to host the Asia America Trade Show for vendors around the world starting Sunday.

Health officials said at least five people have been infected with Zika in this area, including two who live in Miami Beach. One person from Texas, one from New York and another from Taiwan have returned home after being infected while in Miami Beach.

“This situation is very unfortunate. It’s not something we’d wish upon any community,” Miami Beach Mayor Philip Levine said.

The news marks a second front in Miami's fight against local transmission of the virus. Previously, officials had pinpointed local infections in a one-square-mile area north of downtown Miami known as Wynwood. That prompted federal health authorities to urge pregnant women not to visit the area, the first time they ever had warned against travel to a part of the continental United States because of the outbreak of an infectious disease.

The Centers for Disease Control and Prevention quickly issued a second travel advisory Friday afternoon, saying pregnant women should also avoid the designated area of Miami Beach. The agency said that pregnant women who live in the area or have to travel there should take extra precautions to guard against mosquito bites, including wearing repellent. It gave the same direction for these women's sexual partners.

In a call with reporters Friday, CDC director Tom Frieden said Miami Beach presents a difficult situation for health officials trying to halt the Zika outbreak. The area has a constant stream of visitors, many of them international, who could carry the virus elsewhere should they get infected.

In addition, the low-flying planes that have been spraying specialized insecticide over Wynwood cannot do so over Miami Beach because of the high-rise buildings that front the Atlantic Ocean and often windy conditions. And the city's South Beach is a beach, after all, notorious for skimpy bikinis and a general lack of clothing at all hours.

"The amount of exposed skin also makes it harder to prevent infections there," Frieden said. "We think this will be a challenging area."

Scott said Miami-Dade County already had begun an intensified mosquito control campaign in Miami Beach. He sought to reassure state residents -- and especially the tourism industry -- that his administration was doing everything possible to combat more spread of the virus. He said the state would be requesting more resources from the CDC, including additional Zika testing kits.

"Tourism is a driving force of our economy, and this industry has the full support of our state in the fight against the Zika virus," Scott said. "We want to do all we can to ensure Florida remains safe for businesses and our families."

The mayor reiterated similar points late in the afternoon, stressing local officials’ stepped-up mosquito control efforts. “The last thing I’d want to be in Miami Beach right now is a mosquito,” Levine said.

And William Talbert III, president of the Greater Miami Convention & Visitors Bureau, voiced confidence that officials would be able to control the outbreak, that tourists would continue to come given the relatively modest risks to everyone but pregnant women and that the area’s economy would not suffer a serious blow.

The tourism industry employs more people than any other locally. "We've had a record summer," Talbert said.

But while Frieden praised the work of Florida officials and said intense spraying and other efforts had killed many mosquitoes in the Wynwood neighborhood, he noted that the Aedes aegypti mosquito primarily responsible for spreading Zika is resilient.

"It's a tough mosquito to kill," he said. "This is truly the cockroach of mosquitoes."

On Thursday, Scott's office adamantly disputed reports that mosquitoes were transmitting Zika in Miami Beach, despite multiple health officials telling reporters that indeed was the case. In his press conference Friday, the governor faced questions about whether he had tried to obscure evidence of an expanding outbreak, in part to protect the state's massive tourism industry.

He said that state health investigators had only finished their inquiry into the new cases Friday morning and that he had rushed to Miami to deliver the news and meet with local leaders.

"We’re going to provide timely accurate information for public health," Scott said. "I want everybody in this state to stay safe. I want our visitors to stay safe."

The virus, which has now spread to 70 countries, has been linked to a rare and severe birth defect known as microcephaly, which in newborns is characterized by an abnormally small head and often underdeveloped brain, as well as an array of other fetal abnormalities. In rare cases, Zika also has been linked in adults to Guillain-Barré syndrome, an autoimmune disorder that can cause paralysis and even death.

Nationally, there are more than 2,200 confirmed Zika cases in the states and more than 8,000 in U.S. territories, the vast majority of those in Puerto Rico. The CDC is tracking 529 pregnant women with the virus nationwide and nearly 700 in those territories.

The Obama administration has sought nearly $2 billion in emergency appropriations to help fight the spread of Zika, but Congress has been deadlocked for months and left for its summer recess without approving any funding. The administration recently announced plans to reallocate $81 million from other programs at the National Institutes of Health and elsewhere. Still, officials said, the money being used to combat Zika "will be virtually exhausted by the end of the fiscal year” on Sept. 30.

Friday afternoon, the Florida Department of Health reported a total 488 travel-related cases of Zika and 36 locally acquired cases. Sixty-eight cases involve pregnant women. In Miami-Dade, the agency has identified at least four cases of apparently mosquito-borne Zika that occurred outside of the two areas identified for active transmissions.

Celeste Philip, Florida's surgeon general, said Friday that officials have not yet determined where those isolated cases contracted Zika.

"It’s like solving a mystery, it takes time for us to look at all that information and makes connections," Philip said. She added, "I want to assure everyone that if we identify local areas of transmission, we will alert the public and the media immediately."

The clusters of outbreaks around Miami are not a surprise to many health experts, who anticipated that the Zika virus would be tricky to contain after it began spreading locally in the United States. While the Aedes aegypti travels no more than about 500 feet in its lifettime, people have the capacity to quickly carry the virus to the far ends of the globe.

"There are undoubtedly more infections that we are not aware of right now," Frieden said, noting that roughly 80 percent of people infected by Zika never experience symptoms such as fever, rash or joint pain. "We can't predict how long this will continue, but we do know that it will be difficult to control."

Watch: How long until we have a Zika vaccine? (Video: The Washington Post/Photo: Sammy Dallal for The Washington Post)

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