Dengue Fever Is Spreading Locally in Florida — Here’s What to Know Now

For years, a dengue diagnosis in Florida usually came with a question: Where did you travel? Cuba, Brazil, the Dominican Republic, or another part of the world where the mosquito-borne virus regularly circulates were obvious places to look for an explanation.

Increasingly, however, the answer can be nowhere.

Florida is reporting locally acquired dengue infections, meaning people are being infected by mosquitoes close to home rather than picking up the virus while traveling abroad. This summer, Pinellas County recorded its first locally acquired case in more than 15 years, while infections have also been confirmed in other parts of the state.

Dengue is sometimes called “breakbone fever” because of the severe muscle, bone, and joint pain it can cause. Most infections are mild or produce no symptoms at all, but a small proportion can progress to severe illness. And because the Aedes mosquitoes capable of transmitting dengue already live in Florida, an infected traveler can potentially introduce the virus into a local mosquito population and start a small chain of transmission.

That doesn’t mean dengue is suddenly widespread across Florida. But for residents in affected areas, travel is no longer the only way to encounter it, and knowing how it spreads, what symptoms to watch for, and how to reduce mosquito exposure matters more than it once did.

Dengue Fever Florida: How Big Is This Outbreak?

Locally acquired infections have been confirmed in Hillsborough, Miami-Dade, Pinellas, and Palm Beach counties, with Hillsborough, Miami-Dade, and Pinellas under mosquito-borne illness alerts and Palm Beach under a mosquito-borne illness advisory.

A CDC report published in MMWR found that U.S.-reported dengue cases in 2024 reached a record 3,798 – a 359% increase above the 2010 to 2023 annual average. Florida reported the most cases among U.S. states and Washington, D.C., in 2024, with 1,044 infections. Nationally, 97.2% of U.S. dengue cases were travel-associated; the remaining 2.8% were locally acquired. Florida accounted for 85 of the 105 locally acquired cases reported nationwide that year. In the current outbreak, local transmission is the headline story rather than the footnote.

Why the Aedes Mosquito Is the Real Problem

Dengue is transmitted to humans through the bites of infected female mosquitoes, primarily Aedes aegypti. Unlike many species that are active at dusk and dawn, Aedes aegypti bites during daylight hours, putting people outdoors in the middle of the day at risk in a way that dusk-active species do not.

Local transmission taking root in Pinellas County for the first time in over 15 years reflects a pattern public health officials are tracking across the Tampa Bay region: infected travelers arrive, local Aedes aegypti mosquitoes bite them, and those mosquitoes then spread the virus within a small geographic radius. Pinellas County Mosquito Control Director Alissa Berro explained that the mosquitoes doing the spreading generally stay within a relatively small area, but people travel throughout the Tampa Bay area every day – meaning a single infected person moving between counties can seed new transmission chains wherever they go.

Aedes aegypti breeds in domestic and peri-domestic man-made water sources rather than natural wetlands – a bucket left in a backyard after rain, a planter saucer, a discarded tire, a clogged rain gutter. Unlike many mosquito species that travel miles, Aedes aegypti tend to stay close to where they hatch, which means local elimination of breeding sites directly reduces the local mosquito population.

Mosquito control crews in Florida are increasing aerial and ground treatments in areas showing dengue virus activity, while also inspecting private properties for potential mosquito breeding sites. Pesticide applications have focused on areas of central Tampa where locally acquired cases have been identified.

What Dengue Actually Does to the Body

Most people infected with dengue have no symptoms, and most who do become sick recover within a week, according to the CDC. This makes the disease difficult to track, since asymptomatic cases can still infect local mosquitoes, which then spread the virus to others.

For those who do develop symptoms, dengue begins abruptly after an incubation period of 3 to 10 days and presents with fever, severe headache, and bone, muscle, and joint pain. Fever typically lasts 2 to 7 days and can be biphasic – it may briefly subside before returning, which can be mistaken for recovery. The symptoms are similar to influenza and other viruses, which means dengue is often diagnosed incorrectly.

The “breakbone fever” nickname is historical: patients have long described pain severe enough that it felt as though bones were breaking. Dengue does not actually cause bones to break – the pain is simply extreme enough that the description stuck.

Most people who develop dengue symptoms recover within a week. In a minority of patients, however, the period right after the fever drops is when the disease turns dangerous. Warning signs include severe abdominal pain or tenderness, persistent vomiting, unusual bleeding, and difficulty breathing. These signs can emerge within one to two days after the fever drops and can escalate rapidly. In severe cases, health effects can include hemorrhage, shock, and organ failure. Anyone developing these warning signs requires emergency medical care immediately.

There is no antiviral treatment for dengue. Management is supportive – hydration, pain relief, and close monitoring – making early detection of warning signs essential.

A Global Disease Moving Closer to Home

Dengue fever is currently endemic in more than 100 countries and regions, mainly in tropical and subtropical areas of the world. Florida’s warm, humid climate and year-round mosquito activity make it the most vulnerable state in the continental U.S. for local dengue transmission.

Travel history used to be the key risk factor for dengue exposure in Florida. For residents of Hillsborough, Pinellas, Miami-Dade, and Palm Beach counties this season, it no longer is.

What Florida Residents Can Do Right Now

Mosquito control crews are handling aerial and ground-level treatment. Individual residents control something agencies cannot: the breeding sites on private property. The Florida Mosquito Control Association is urging Floridians to take precautions and help mosquito control professionals reduce the risk of mosquito-borne illnesses across the state.

Aedes aegypti breeds in tiny amounts of standing water, which means even a bottle cap can serve as a nursery. Emptying containers after rain, covering water storage barrels, and checking for clogged gutters and forgotten plant saucers can directly reduce the population of dengue-carrying mosquitoes around a home.

For personal protection, the CDC recommends products containing DEET, picaridin, IR3535, or oil of lemon eucalyptus. Since Aedes aegypti bites during daylight hours, applying repellent in the morning before outdoor activity – not just at dusk – is essential. Covering skin with long sleeves and light-colored clothing adds another layer of protection.

If you develop a sudden high fever with severe body aches, a rash, or pain behind the eyes within two weeks of spending time outdoors in one of the affected counties, tell your doctor about potential dengue exposure. Many physicians in non-endemic areas don’t think to test for it, and the similarity to flu means it gets missed. Early diagnosis matters, especially for catching the warning signs of severe dengue before they escalate.

What This Means for You

Dengue remains far less common in Florida than in parts of the world where the virus circulates routinely, and a handful of local transmission clusters does not mean every mosquito bite is a serious threat. What has changed is the assumption that dengue in Florida is almost exclusively a travel-related illness.

For people living in affected counties, prevention comes down largely to avoiding mosquito bites and making it harder for Aedes mosquitoes to breed around the home. That means using an effective repellent, remembering that these mosquitoes also bite during the day, and regularly emptying small containers of standing water.

Most people who develop dengue recover, but knowing the warning signs of severe disease matters. Severe abdominal pain, persistent vomiting, unusual bleeding, or difficulty breathing, particularly as a fever begins to subside, warrant immediate medical attention.

Florida isn’t becoming a dengue-endemic region overnight. But locally acquired cases show that the virus doesn’t necessarily require an international trip anymore. Sometimes the mosquito carrying it may already be close to home.

Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.

AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.

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