Written By | Health News Agencies
More than 250 locally caught cases, one death, three counties under emergency orders and helicopters spraying day and night over Tampa. Now Broward County has its first local case.
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A city under the mosquito siege
The helicopters come in low over the rooftops of East Tampa, Palm River and Bloomingdale, trailing a fine mist of pesticide. Some fly by night. Some, this week, fly in broad daylight. On the ground, crews are going door to door, tipping out flowerpots, hunting through backyards for old tyres full of rainwater, and spraying anywhere a mosquito might breed.
This is what the frontline looks like in the largest dengue outbreak the continental United States has seen in generations.
According to the Florida Department of Health, the state recorded 252 locally acquired cases of dengue fever from July through September 26. That means people caught the virus from mosquitoes right here in Florida, not on a trip abroad. The vast majority, 223 cases, are in Hillsborough County, home to Tampa. Neighboring Pinellas County has 13 and Pasco County has three.
Federal officials admit their records on dengue outbreaks are patchy. But according to an Associated Press analysis of state health department data and medical journals, Florida's 2026 outbreak marks the most locally spread cases in a single calendar year for any US state since at least the 1940s. Puerto Rico, where dengue is a constant presence, routinely sees far higher numbers. But on the mainland, nothing in living memory has come close.
And it is not over. On Monday, October 5, the health department in Broward County, on the other side of the state, reported its first locally acquired case of the year and issued a mosquito-borne illness advisory. Broward is the eighth Florida county to confirm a locally caught case during the current outbreak.
How fast it grew
The numbers have climbed at alarming speed. For the week ending September 19, the state counted at least 190 locally acquired cases, with 170 of them in Hillsborough, ABC News reported. One week later, the total had jumped past 250. Public radio station WUSF reported on October 2 that Hillsborough had added 53 cases in a single update.
The previous record year for Florida was 2023, when just under 200 locally spread cases were reported across the whole state. The largest outbreak in any US state since 1945 struck Hawaii in 2015 and 2016, with 264 locally acquired cases over six months. The Tampa-area outbreak, which first came to light in July, is now on the verge of overtaking it.
For decades, almost every dengue case diagnosed in the continental US was in someone who had caught the virus while traveling. That changed in 2009 and 2010, when Key West reported the first cases acquired in the continental US outside the Texas-Mexico border since 1945. Since then, local outbreaks have become more frequent. This year, for the first time, Florida's locally caught cases have actually overtaken travel-related ones, by 252 to 245 as of late September.
The outbreak has already been deadly. An elderly Tampa woman died of dengue on September 4, the state's first dengue death of the year.
Emergency orders and borrowed helicopters
Last month, Hillsborough, Pasco and Pinellas counties all declared local states of emergency. On October 1, Hillsborough County Administrator Bonnie Wise signed an executive order extending the county's emergency to October 8. Under county rules, a local emergency lasts only seven days unless it is renewed.
The declaration lets officials act quickly, waive normal procedures and open a path to federal reimbursement for some costs. According to the county, mosquito surveillance "in many neighborhoods is showing dengue virus activity in the mosquito population," meaning infected mosquitoes are being caught in traps across the area. Crews are stepping up treatments by air and by ground, and neighboring Lee County's mosquito control district has sent helicopters and contractors to help.
In Pinellas County, crews have been going door to door to spray high-mosquito areas, according to local ABC affiliate WFTS. Across the state, the health department has placed Alachua, Duval, Hillsborough, Miami-Dade, Orange, Pasco and Pinellas counties under a mosquito-borne illness alert, its higher level of warning. Brevard, Broward, Leon, Palm Beach, Polk and Walton counties are under an advisory.
Where is the CDC?
In past outbreaks of this size, the US Centers for Disease Control and Prevention would have been highly visible, with its "disease detectives" on the ground. Not this time.
"Traditionally, the CDC would be highly visible in a situation like this, but it hasn't been this time," noted Dawn Wesson, a Tulane University expert on mosquito-borne diseases.
The reason is procedural: the CDC has to be invited in by state officials, and Florida has not asked for its investigators, CDC spokesman Jason McDonald told the Associated Press. The agency has given the state health department $800,000 in emergency funding. In a statement to ABC News, the CDC said it was "closely tracking dengue activity" and the "unprecedented" number of cases in the Tampa area.
"Because the types of mosquitoes that spread dengue, Aedes aegypti, are common throughout many areas of the United States, continued local spread of dengue is possible," the agency warned.
What is dengue, and why do they call it 'breakbone fever'?
Dengue (pronounced DEN-gay) is a virus spread by the bite of infected Aedes mosquitoes. Most infected people never feel ill. But some develop a high fever, headache, rash, pain behind the eyes and intense muscle and joint pain. The aches can be so excruciating that the illness earned the nickname "breakbone fever."
A small share of patients develop severe dengue, which can cause internal bleeding, shock and death. The danger often peaks just as the fever is breaking, when patients may think they are getting better.
There is a cruel twist. Dengue comes in four types, known simply as 1, 2, 3 and 4. Catching one type gives you lifelong protection against that type. But if you later catch a different type, the antibodies from your first infection can actually help the new virus get into your cells and multiply, making a second infection more likely to be severe. That is a big reason why building a safe dengue vaccine has been so difficult. Wesson said most people in the Tampa area have no prior immunity to any type, which helps explain how quickly the virus has spread.
Worldwide, the World Health Organization has counted more than 2.2 million infections and nearly 1,200 deaths so far this year. The CDC reports nearly 1,900 locally acquired US cases in 2026, most of them in Puerto Rico.
Expert perspective: "The top of an iceberg"
Experts say the official count almost certainly underestimates the true size of the outbreak.
"I don't recall a [period] of time when it's been this high in such a sort of concentrated area before," Cameron Wolfe, an infectious diseases specialist and professor of medicine at Duke University School of Medicine, told ABC News. Many cases are mild, people recover on their own without testing, and the illness is easily mistaken for flu. "For every case that we know, there's going to be a bunch that we never find out about," Wolfe said.
Natalie Dean, an associate professor of biostatistics at Emory University's Rollins School of Public Health, agreed. "Dengue is not endemic to the United States. That means that it doesn't typically cause local transmission," she told ABC News. "There can be occasional outbreaks in the U.S. but this one is notable for its size." She added: "I always think of like the top of an iceberg. We're only capturing some of the cases."
Why Tampa, and why now? Wesson said Florida sees a lot of dengue partly because it receives so many travelers from Puerto Rico and other places where the disease is common. Infected travelers get bitten by local mosquitoes, which then pass the virus on to neighbors. Usually the action is around Miami. It is hard to say exactly what changed in the Tampa area this year, she said, though travel patterns may be part of it.
Climate is the bigger worry. The heat-loving mosquitoes that carry dengue are expanding their range, and warmer, wetter conditions create more standing water where they breed. "Global warming and climate change, in fact, leave places like Florida more wet and more capable of housing these mosquito vectors, so I wouldn't be surprised if this becomes a little more of a perpetual thing," Wolfe said.
Wesson put it more bluntly: "There's a good chance that this is the new normal."
What this means for you
If you live in or are visiting Florida, especially the Tampa Bay area, here is how to protect yourself and your family:
The bottom line
Florida has lived with mosquitoes for as long as there has been a Florida. But 2026 has shown what happens when a tropical virus finds a population with no immunity and a climate that suits its carriers just fine.
More than 250 people have caught dengue in their own neighborhoods this year. One has died. Emergency orders are being renewed week by week, helicopters are borrowed from neighboring counties, and the virus has now turned up on the Atlantic coast in Broward. With mosquito season stretching later into the year, officials are urging residents not to let their guard down just because summer is over.
The spraying will continue. The case count will almost certainly rise. And if the experts are right, Floridians may need to get used to a disease most of them had barely heard of a few years ago.
