Health
NewsOnScale Staff
October 4, 2026
Three Florida counties have declared states of emergency over a dengue fever outbreak that health officials are calling the largest in the United States in decades.
Dengue fever is a mosquito-borne viral illness that causes high fever, severe headache, joint and muscle pain, and in serious cases, hemorrhagic fever that can be fatal. There is no specific treatment. Prevention relies on mosquito control and avoiding bites.
The current outbreak has killed more than 4,000 people according to health authorities tracking the global spread, as the virus has moved through multiple countries. Florida's cases are locally transmitted, meaning people are being infected here, not just traveling back with the virus from abroad.
The outbreak arrives several years after two high-profile genetically modified mosquito release programs were conducted in Florida. Starting in 2021, Oxitec — funded in part by the Bill and Melinda Gates Foundation — released hundreds of millions of genetically modified Aedes aegypti mosquitoes in the Florida Keys, designed to reduce mosquito populations by producing offspring that die before adulthood. Around the same time, Verily, Google's life sciences subsidiary, ran a similar sterile mosquito release program called Debug in other parts of the country. Both programs were approved by the EPA and Florida health authorities. Questions about the long-term effects of those releases on Florida's mosquito population and disease transmission patterns have not been fully answered by public health researchers.
Florida's warm, humid climate makes it hospitable to the Aedes aegypti mosquito that carries dengue. The state has seen small clusters of local transmission in previous years, but this outbreak is drawing comparisons to dengue seasons seen in Puerto Rico and other tropical regions rather than anything previously recorded in the continental United States.
The counties that have declared emergencies have ramped up mosquito control operations including aerial spraying. Residents are being advised to eliminate standing water around their homes, use EPA-registered insect repellent, and wear long sleeves and pants during peak mosquito hours.
Dengue typically appears four to ten days after a mosquito bite. Early symptoms include sudden high fever, severe headaches, pain behind the eyes, and muscle and joint pain. Anyone experiencing these symptoms after potential mosquito exposure should seek medical attention and mention the possibility of dengue to their doctor.
The Florida Department of Health has current information at floridahealth.gov.
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