Locally Acquired Dengue Fever Cases Confirmed in Palm Beach and Miami-Dade Counties, Florida Health Officials Issue Mosquito Protection Alert
Key Insights
The Florida Department of Health (search) confirmed locally transmitted dengue fever (search) cases in Palm Beach County and Miami-Dade County, prompting mosquito protection advisories.
Florida remains the highest-risk state for locally acquired dengue in the continental U.S., with approximately 50 cases reported through July 2026 and over 500 cases nationwide.
Dengue is transmitted by Aedes aegypti and Aedes albopictus mosquitoes; peak transmission season runs from July through September.
The Florida Department of Health (search) in Palm Beach County (DOH-Palm Beach) and Miami-Dade health officials issued alerts Monday urging residents to increase personal mosquito protection after locally transmitted dengue fever (search) cases were confirmed in both counties. This marks the second local transmission of dengue in Florida this year, following a recently reported case in Hillsborough County.
DOH-Palm Beach and Palm Beach County Mosquito Control are coordinating surveillance and prevention efforts, including larvicide spraying in areas to reduce mosquito-breeding habitats across South Florida.
Transmission and Peak Season
Dengue fever (search) is transmitted by the same type of daytime-biting mosquito that spreads other viral infections, including chikungunya (search). The primary vector is Aedes aegypti, though Aedes albopictus—also present in Florida—can transmit the virus as well. July through September represents the highest-risk window of the year for dengue cases.
Researchers at the University of Florida's Emerging Pathogens Institute have linked the abundance of Aedes aegypti mosquitoes in Florida to conditions such as high temperatures and substantial rainfall, which have enabled more frequent local transmission of dengue and chikungunya (search). The majority of dengue fever (search) cases remain travel-associated, most often acquired in the Caribbean, Central America, or Mexico. However, returning travelers are seeding the virus into areas with large mosquito populations, according to the CDC.
Clinical Presentation and Disease Course
Symptoms appear 3–14 days after the bite of an infected mosquito and include sudden onset of fever, severe headache, pain behind the eyes, muscle and joint pain—giving the disease the nickname "breakbone fever"—as well as nausea, vomiting, swollen glands, and a skin rash. Gastrointestinal symptoms like vomiting and diarrhea may also be present in some cases.
Dengue fever (search) symptoms usually last 4–7 days. The disease is often diagnosed incorrectly because the symptoms are similar to influenza and other viruses. Most people recover within one to two weeks.
Severe dengue, more likely in people experiencing a second infection, can cause bleeding under the skin, gum or nose bleeds, blood in urine or stool, persistent vomiting, abdominal pain, rapid breathing, fatigue, and restlessness. Dengue hemorrhagic fever is a rare but more severe form of dengue infection that can be fatal if not recognized and treated with supportive care. There is no specific treatment for dengue fever (search) or dengue hemorrhagic fever, but quick recognition and management of symptoms and complications is effective at preventing deaths.
Epidemiological Context
Despite mosquito-control efforts, South Florida had one of the highest counts of dengue cases in the country in 2025. Florida remains the highest-risk state for locally acquired dengue in the continental United States, with about 50 cases reported through July, according to the Centers for Disease Control and Prevention (search). Nationwide, dengue fever (search) has surpassed 500 cases in 2026, following a record-breaking 2024 that saw 3,798 confirmed cases reported to the CDC's ArboNET surveillance system.
Prevention and Concurrent Threats
Disease experts emphasize that DEET remains one of the most effective preventive measures against mosquitoes and should be reapplied often when outside during this time of year. Dengue fever (search) spreads through mosquito bites, not from person to person through bodily fluids or contact.
Adding urgency to the advisory, the CDC is seeing the earliest start to the West Nile virus (search) season in the United States, with the highest number of human disease cases reported by this time of year since 2004.