Florida added 41 locally acquired dengue cases in a single week, the largest weekly increase reported this year, pushing the state's 2026 total to 152 infections acquired without travel. Thirty-nine of the new cases were in Hillsborough County.
The figures come from data the Florida Department of Health released Sept. 17 covering the week of Sept. 6 to 12, reported by WTSP. Hillsborough County alone now accounts for 134 of the state's 152 local cases.
That concentration is the part Tampa Bay households should absorb. This is not a statewide scatter of isolated infections. Three adjacent counties, Hillsborough, Pinellas and Pasco, account for 143 of the 152 local cases, which means the mosquitoes carrying the virus are breeding in neighborhoods where people live, park their cars and store their yard equipment.
One Week Added More Cases Than Some Entire Years
Local transmission in Florida climbed quickly through the late summer. State surveillance recorded 21 local cases with onset in July, 124 in August and seven so far in September, according to a review of the state's arbovirus data. Beyond Hillsborough, cases have been reported in Pinellas, Miami-Dade, Pasco, Orange and Palm Beach counties.
Travel-associated dengue is counted separately and has reached 186 cases this year, with most tied to travel to Cuba, WFLA reported. Those imported infections are what seed local outbreaks: a mosquito bites a returning traveler, then bites a neighbor who has not left the country.
Duval, Hillsborough, Miami-Dade and Pinellas counties are under a mosquito-borne illness alert. The Florida Department of Health in Hillsborough County has issued repeated public alerts as case counts rose through the summer, working alongside Hillsborough County Mosquito Management on trapping and treatment.
The state has also reported its first locally acquired chikungunya case of the year, in Miami-Dade County. Chikungunya is a separate virus spread by the same Aedes mosquitoes.
Standing Water in Ordinary Places Is Driving Spread
Florida Surgeon General Joseph Ladapo described Hillsborough as the center of local transmission earlier this month, when the county had reported about 59 cases. "Hillsborough County is really the epicenter of it," he said, according to WFLA.
County crews have traced much of the mosquito breeding to containers that hold rainwater, including discarded tires. At one tire business, mosquito management staff initially collected 1,145 female mosquitoes, a number that fell to six after treatment. Fourteen mosquito pools had tested positive for dengue at that point in the investigation.
Health officials are also investigating whether dengue caused the death of a Hillsborough County resident, as WUSF has reported. The department has not attributed the death to dengue and, citing privacy rules, has not released further details.
A feature of dengue makes containment harder than it looks. Many infected people never feel sick but can still pass the virus to mosquitoes that bite them. Carla Fry, administrator and health officer for the Florida Department of Health in Hillsborough County, told WFLA that "so many people are running around asymptomatic, they can be spreading it"onward through mosquito bites, in comments on the county's outbreak. Officials say the true case count is almost certainly higher than what is reported, because milder infections never reach a doctor.
Repeat Infection and Pregnancy Raise the Stakes
Most people who get dengue recover in about a week with rest and fluids. There is no specific antiviral treatment.
The people who face the most serious risk are those who have had dengue before with a different serotype, pregnant women, infants, and older adults with underlying conditions. A second infection with a different strain carries a higher chance of severe dengue, which can involve internal bleeding and shock and requires prompt hospital care. Nearly all of Florida's typed local cases this year have been DENV-2, so the concern in Tampa Bay is chiefly for people who were infected with a different serotype somewhere else.
Symptoms usually begin three to 14 days after a bite and include sudden fever, severe headache, pain behind the eyes, and muscle and joint pain intense enough to earn dengue the nickname breakbone fever. Nausea, vomiting, and rash are common. Respiratory symptoms usually are not present, which is one way clinicians distinguish it from flu.
Warning signs that call for immediate medical attention include severe abdominal pain, persistent vomiting, bleeding from the gums or nose, blood in vomit or stool, and sudden weakness after the fever breaks. Health officials note that people with suspected dengue should avoid aspirin and ibuprofen because of bleeding risk, and should ask a clinician what pain reliever is appropriate.
The most useful household step is unglamorous. Drain anything that holds water at least twice a week, including plant saucers, buckets, toys, birdbaths, pool covers and clogged gutters. Even a bottle cap of standing water can support breeding. Repair torn window and door screens. Use insect repellents registered by the Environmental Protection Agency, which the health department says are proven safe and effective when used as directed, including for pregnant and breastfeeding women. Long sleeves and pants help, and the mosquitoes that carry dengue bite during the day, with peak activity near sunrise and sunset.
What remains unknown is how long transmission will continue. Mosquito activity typically declines as Florida cools, but the state has not projected an end date, and case counts lag infection. The next state surveillance update is expected within the week, and MedicalDaily will follow county-level totals as they are released.
Key Questions Answered
How many dengue cases has Florida confirmed? The state reported 152 locally acquired cases in 2026 as of data released Sept. 17, including 134 in Hillsborough County, seven in Pinellas, seven in Miami-Dade, and two in Pasco. A separate 186 cases were travel-associated.
What does locally acquired mean? It means the person was infected by a mosquito bite in Florida rather than while traveling abroad. Local transmission indicates the virus is circulating between mosquitoes and people in the community.
Which counties are under alert? Duval, Hillsborough, Miami-Dade, and Pinellas counties are under a mosquito-borne illness alert issued by the Florida Department of Health.
What are the symptoms of dengue? Sudden fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, and sometimes a rash, typically starting three to 14 days after a bite. Respiratory symptoms are usually absent.
Who is most at risk of severe illness? People previously infected with a different dengue serotype, pregnant women, infants, and older adults with chronic conditions face the highest risk of severe dengue.
Is there a treatment or vaccine? There is no specific antiviral treatment, and care is supportive. Prevention focuses on avoiding bites and eliminating standing water where mosquitoes breed.
What should residents do this week? Empty containers holding water twice weekly, repair screens, use EPA-registered repellent, and contact a clinician for fever with severe headache or joint pain, especially after being bitten.
