Florida health officials have reported more than 250 locally acquired dengue cases this year, most of them in Hillsborough County, home to Tampa. Officials in Hillsborough and nearby counties have declared local emergencies. The outbreak centers just north of Tampa, where workers spray for mosquitoes day and night and inspect properties for pooled water.
A state-led response, a household-level burden
The outbreak first came to light in July. As of last week, Florida had recorded more locally acquired cases than travel-associated cases: 252 to 245. At least 13 Hillsborough County cases involved travelers, according to the state.
County officials and workers lead the documented response. The account describes no mutual-aid effort or community-organized response; instead, residents are urged to inspect their properties and remove pooled water where mosquitoes might breed. That leaves one part of the immediate prevention work to households, alongside government spraying and property checks.
Dengue spreads through a type of mosquito. Many infected people don't get sick. Others develop fever, flu-like symptoms and aches. The disease is nicknamed “breakbone fever” because some people experience severe pain. Severe cases can cause bleeding, shock and death.
Florida has reported one dengue death this year: an elderly Tampa woman who died Sept. 4. As the state responds, residents face infection risks and recommendations to use insect repellent, cover their skin and reduce places where mosquitoes can breed.
What the numbers show—and what they don't
The outbreak appears to be the largest in several decades in the continental United States. Florida’s more than 250 locally acquired cases are nearing the record set during a six-month dengue outbreak in Hawaii in 2015-2016, when officials reported 264 locally acquired cases.
Available information from state health departments and medical journals suggests Florida has recorded more cases in a calendar year than any other state since at least the 1940s, federal health officials said. They cautioned, though, that their data on dengue outbreaks is limited. Puerto Rico is consistently hit hard, with numbers far higher than those in any of the 50 states. Florida usually has the most locally transmitted cases in the continental United States; its previous worst year came in 2023, when officials reported just under 200 locally spread cases.
The Centers for Disease Control and Prevention hasn't sent disease investigators to Florida. Dawn Wesson, a Tulane University expert on dengue and other diseases spread by mosquitoes, said the agency would traditionally be highly visible in a situation like this, but it hasn't been this time. CDC spokesman Jason McDonald said state officials must invite the agency in, and Florida officials hadn't asked investigators to come. He said the agency provided $800,000 in assistance to the state health department.
The limits of individual precautions
Wesson said travel patterns may partly explain the Tampa-area surge, though she said it was hard to say what was driving it. Florida tends to see many cases partly because travelers arrive from Puerto Rico and other places where dengue is present; cases are usually concentrated in southern Florida, around Miami.
Mosquitoes that spread dengue live in Florida and some other hotter U.S. locations. Experts say climate change has helped them expand their geographic reach. Wesson said climate conditions and persistent mosquito populations will likely make local outbreaks more frequent. “There's a good chance that this is the new normal,” she said.
Experts recommend EPA-registered insect repellents containing active ingredients such as DEET, loose-fitting long sleeves and pants, and staying indoors behind screens or in air-conditioned rooms. Mosquitoes can bite at any time of day. Activity often peaks just after sunrise and around sunset. The instructions are practical, but residents still face a long list of precautions while the outbreak continues.