Dengue Fever in Florida: Local Transmission, Risk Areas, and What South Florida Residents Need to Know

Yes — local dengue transmission has been documented in Florida, including in South Florida. Local transmission means individuals contracted dengue from mosquitoes in Florida — not from travel abroad: (1) 2022–2023: Florida recorded the highest number of locally-acquired dengue cases in the continental United States, with cases confirmed in Miami-Dade, Broward, Palm Beach, and other counties. The Florida Department of Health issued dengue advisories for specific neighborhoods during these outbreaks. (2) 2023–2024: Additional local transmission continued to be documented. South Florida's densely populated urban and suburban areas, combined with high Aedes aegypti mosquito populations, create conditions for sustained local cycles when imported cases introduce the virus. (3) The pattern: Local dengue transmission in Florida typically begins when a traveler infected abroad returns home and is bitten by a local Aedes aegypti. That mosquito then transmits the virus to other people in the community, establishing a local transmission chain. Breaking this chain requires controlling the Aedes mosquito population. (4) This is different from the historical pattern: Historically, most Florida dengue cases were imported (travelers returning from endemic countries). Local transmission in South Florida is a more recent and concerning development.

Dengue fever produces a distinctive symptom pattern: (1) High fever — sudden onset, typically 104°F (40°C), lasting 2–7 days. One of the most characteristic features is the abrupt onset of high fever. (2) Severe headache — frontal, behind the eyes (retro-orbital pain is a dengue hallmark), and generalized. (3) Severe joint and muscle pain — dengue is historically called 'breakbone fever' due to the intensity of joint and bone pain that accompanies the fever. (4) Skin rash — a flat or slightly raised rash typically appears 3–4 days after fever onset. (5) Nausea and vomiting. (6) Mild bleeding — easy bruising, minor bleeding from the nose or gums. (7) Warning signs for severe dengue (seek emergency care): abdominal pain or tenderness, persistent vomiting, bleeding from gums, rapid breathing, fatigue, restlessness. Severe dengue (dengue hemorrhagic fever) can be life-threatening and requires immediate medical attention. (8) If you have these symptoms and have been in an area with Aedes mosquitoes (which includes all of South Florida), tell your doctor about potential dengue exposure. Many Florida primary care physicians now include dengue in their differential diagnosis for febrile illness.

The primary dengue vector is Aedes aegypti — and it is abundant in Boca Raton, Fort Lauderdale, Pompano Beach, Coral Springs, and throughout our service territory: (1) Where Aedes aegypti lives: This species is a residential, day-biting mosquito that lives in close proximity to humans. It breeds in small containers of water in residential yards — bromeliads, bird baths, ornamental containers, flower pots, pool covers, tarps, and any other object that holds standing water. Unlike Culex mosquitoes that breed in canals, Aedes aegypti breeds ON your property. (2) Why it's the perfect dengue vector: Aedes aegypti bites humans almost exclusively (unlike Culex, which bites birds too). It bites multiple people in a single feeding, making it highly efficient at spreading dengue between humans in a neighborhood. It doesn't travel far from its breeding site, which is why local dengue outbreaks tend to be neighborhood-specific. (3) Two peak biting periods: Aedes aegypti is active in the morning (2 hours after sunrise) and late afternoon — unlike the dusk/night activity of Culex. You can be bitten in your yard while gardening in the morning or swimming in the afternoon. (4) Is it in your neighborhood? Yes — Aedes aegypti is established throughout South Florida's residential areas. Every neighborhood with ornamental landscaping (especially bromeliads) has established populations.

Protection from dengue in South Florida requires a combination of source control, personal protection, and professional mosquito control: (1) Professional barrier spray — the most effective way to reduce Aedes aegypti populations in your yard is professional barrier spray applied to vegetation where adult mosquitoes rest. Our MPB barrier spray targets the ornamental plants and shaded vegetation where Aedes aegypti rests between feedings, applying a residual product that kills adult mosquitoes and reduces the population that can transmit dengue. Biweekly application maintains continuous protection. (2) Source control on your property — Aedes aegypti breeds in small containers. Weekly drain and tip: empty anything that holds water (bromeliads need to be flushed with a hose to flush larvae), cover or remove any containers, treat bird baths with Bti dunks, change pet water bowls daily. (3) Personal repellent — when outdoors during Aedes aegypti biting hours (morning and late afternoon), use EPA-approved repellent: 25% DEET, 20% Picaridin, or IR3535. Repellent protects the individual; barrier spray protects the property. (4) Mosquito-proof the home — ensure all windows and doors have intact screens. Replace damaged screens immediately. Dengue is transmitted outdoors but screen integrity protects those inside. (5) Monitor Florida DOH alerts — the Florida Department of Health issues neighborhood-specific advisories during local dengue transmission events. Subscribe to Broward or Palm Beach County health department alerts.

Dengue receives less public attention than it deserves in South Florida for several reasons: (1) Underdiagnosis — many dengue cases in Florida are misdiagnosed as other febrile illnesses (influenza, viral syndrome, chikungunya). Without specific dengue testing, cases aren't counted. The CDC estimates that reported cases significantly undercount actual dengue infections. (2) Mild illness in most people — approximately 75% of dengue infections produce mild or no symptoms. The severe cases that require hospitalization are a minority, so most local transmission doesn't generate emergency room visits that would prompt public health alerts. (3) Media competition — dengue competes for attention with other Florida health stories. Health departments tend to issue targeted alerts rather than broad public campaigns, which limits public awareness. (4) Travel history bias — historically, Florida dengue was a traveler's disease. The shift to local transmission is relatively recent (2020s) and public messaging hasn't fully caught up. (5) What this means for residents: the absence of widespread news coverage doesn't mean the risk is low. South Florida's Aedes aegypti populations are substantial and capable of sustaining local dengue transmission when the virus is introduced. The best protection is maintaining the mosquito control that reduces Aedes populations on and around your property — the same measures that protect against Zika and chikungunya.