Florida health officials have reported more than 250 locally acquired dengue cases this year. In the Tampa area, workers spray for mosquitoes day and night and inspect properties for pooled water. Most cases are in Hillsborough County, home to Tampa, where officials and neighboring counties have declared local emergencies.
The outbreak and its toll
As of last week, locally acquired Florida cases had surpassed travel-associated cases, 252 to 245. The state said at least 13 Hillsborough County cases were diagnosed in travelers. The outbreak is centered just north of Tampa and first came to light in July.
Florida’s case count is nearing the record set during a six-month dengue outbreak in Hawaii in 2015-2016, when officials reported 264 locally acquired cases. Federal health officials said available information from state health departments and medical journals suggests Florida has recorded the most cases in a calendar year for any state since at least the 1940s, though they cautioned that data on dengue outbreaks is limited.
Florida reported one dengue death this year: an elderly Tampa woman who died Sept. 4. Mosquitoes spread the virus that causes dengue. Many infected people don't become sick; others develop fever, flu-like symptoms and aches. The disease is called “breakbone fever” because of the severe pain some people experience. Severe cases can cause bleeding, shock and death.
Workers and public response
In the Tampa area, workers spray to reduce disease-transmitting mosquitoes and check properties for pooled water, including water in tires where mosquitoes might breed. Hillsborough and surrounding counties have declared local emergencies. The article does not report a union, organized worker action, or a labor dispute related to the response.
Wesson said the CDC would traditionally be highly visible in a situation like this, but it hasn't been this time. CDC spokesman Jason McDonald said state officials must invite the agency, and Florida officials hadn't asked CDC disease investigators to come. The agency provided $800,000 in assistance to the state health department, he said.
Prevention and the limits of immunity
Experts recommend EPA-registered insect repellents containing active ingredients such as DEET, loose-fitting long-sleeved shirts and long pants, and staying indoors behind screens or in air-conditioned rooms. Mosquitoes can bite at any time of day, researchers say, although they tend to be most active just after sunrise and around sunset. People in affected areas should check their properties and remove pooled water where mosquitoes might breed.
Four types of dengue virus are known as 1, 2, 3 and 4. A first infection builds lifelong antibodies against that type. If a person later contracts another type, antibodies from the first infection may fail to neutralize it and may help the virus enter immune cells and replicate, complicating efforts to develop an effective vaccine. Most people in the Tampa area don't have prior immunity to any form of dengue, said Dawn Wesson, a Tulane University expert on dengue and other diseases spread by mosquitoes.
Florida usually has the most locally transmitted cases in the continental United States. Its previous worst year was 2023, with just under 200 locally spread cases. Mosquitoes that transmit dengue live in Florida and other hotter U.S. locations, and experts say climate change is expanding their geographic reach. Wesson said travel patterns may partly explain this year's Tampa-area surge, and that climate conditions and persistent mosquito populations will likely make local outbreaks more frequent. “There's a good chance that this is the new normal,” she said.