Florida dengue outbreak becomes largest in continental US in decades with 252 cases

Florida is experiencing its largest dengue outbreak in decades, with 252 locally acquired cases reported as of late September 2026. The outbreak is heavily concentrated in Hillsborough County, which has recorded 223 cases and one death of an elderly Tampa woman. In response, Hillsborough, Pinellas, and Pasco counties have declared local states of emergency to ramp up mosquito-control efforts. The CDC has provided $800,000 in emergency funding, though federal investigators have not been requested by state officials.

Locally acquired cases in Florida

• ▪Florida recorded 252 locally acquired dengue cases in 2026 as of late September, surpassing the state's previous annual high of just under 200 cases in 2023.
• ▪Hillsborough County, which encompasses the Tampa area, reported the highest concentration of Florida's locally acquired dengue cases with 223 infections.

Comparison to past US outbreaks

• ▪Florida's 2026 dengue outbreak appears to be the largest reported by a state in the continental United States in a single year since at least the 1940s.
• ▪The largest dengue outbreak in any U.S. state since 1945 occurred in Hawaii, where 264 locally acquired cases were reported over six months in 2015 and 2016.

Local states of emergency

• ▪Hillsborough, Pinellas, and Pasco counties declared local states of emergency to accelerate mosquito-control efforts and eliminate standing water.
• ▪Hillsborough County Administrator Bonnie Wise extended the local state of emergency on October 1, 2026, to continue mosquito population control efforts.

Travel-associated dengue cases

• ▪The Centers for Disease Control and Prevention reported that most dengue cases in the continental United States are linked to international travel.
• ▪Florida recorded 245 travel-associated dengue cases in 2026, with at least 13 of those cases diagnosed in travelers in Hillsborough County.

Dengue transmission and symptoms

• ▪Dengue symptoms include sudden fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, and sometimes a rash.
• ▪Dengue is a viral infection spread primarily through the bites of infected Aedes aegypti and Aedes albopictus mosquitoes, which are both found in Florida.
• ▪There are four types of dengue virus, and a secondary infection with a different type can cause antibodies from the first infection to facilitate viral replication.

Debatable claims

• ▪Florida's record dengue outbreak represents a permanent new normal for the state
• ▪Climate change is the primary driver of Florida's record dengue outbreak
• ▪Florida should invite CDC disease investigators to manage the dengue outbreak
• ▪Florida counties are justified in declaring emergencies over the dengue outbreak