Florida health officials reported this week that 252 locally acquired dengue cases have been tallied statewide so far this year, as of late September, the vast majority in Hillsborough County, home to Tampa. Another 245 cases were travel-associated. The Associated Press reports it appears to be the largest dengue outbreak in the continental United States in several decades.
Federal health officials caution that national dengue surveillance data is limited, but available state health department data and medical journals suggest Florida's total is the most locally acquired cases in a calendar year for any continental US state since at least the 1940s. The state's previous worst year was 2023, with just under 200 cases. The tally is approaching the largest US state outbreak on record: 264 local infections in Hawaii over six months in 2015 and 2016.
Hillsborough County accounts for 223 locally spread cases, making it the epicenter. The county is Florida's fourth most populous. An elderly Tampa woman died on September 4, the state's only reported dengue death this year. At least 13 Hillsborough cases involved people with recent travel history, showing imported and local transmission overlapping.
Hillsborough, Pasco and Pinellas counties have declared local states of emergency, with Hillsborough County Administrator Bonnie Wise extending the order this week. Crews in the Tampa area are spraying day and night to tamp down mosquito populations, while officials urge residents to drain standing water, wear protective clothing and use insect repellent.
Dengue is caused by a virus spread mainly through bites from Aedes aegypti and Aedes albopictus mosquitoes, both found in Florida. Many infected people have no symptoms; those who fall ill can develop sudden fever, severe headache, pain behind the eyes, muscle and joint pain, and nausea — the excruciating aches earned it the nickname "breakbone fever." Severe cases can cause bleeding, shock and death, and a second infection raises the risk of severe illness. Persistent vomiting, severe abdominal pain, rapid breathing or bleeding are warning signs requiring immediate care.
The outbreak unfolds against record dengue activity across Latin America and the Caribbean over the last two years, with tens of millions of suspected infections. Florida, a major gateway for travel to and from the region, sees infected travelers seed local mosquito populations. Researchers point to frequent international travel, dense urban development and a warming climate favoring Aedes aegypti — and warn that without sustained mosquito control and early detection, repeated seasonal outbreaks will remain a risk. Travelers heading to Florida for winter and spring getaways are being urged to guard against mosquito bites.