HILLSBOROUGH COUNTY, FL — Health officials in Florida have issued mosquito-borne illness alerts after locally acquired dengue cases were reported in Hillsborough and Pinellas counties. The virus, often called breakbone fever, is known for causing severe aches and pain in the muscles, joints and bones, along with pain behind the eyes.
At least 10 locally acquired cases have been reported in the state, according to county and federal health information cited by officials. The warnings come as the summer mosquito season continues and public health agencies urge residents to watch for symptoms and reduce exposure to mosquito bites.
Hillsborough and Pinellas report locally acquired infections
Hillsborough County reported eight locally acquired dengue cases and placed the area under a mosquito-borne illness alert. Pinellas County reported two locally acquired cases. Both counties are on Florida’s Gulf Coast and issued their warnings in mid-August as officials tracked possible local spread.
The Florida reports matter because most dengue cases in the United States are tied to travel, not community transmission. Local spread means the virus was likely passed by mosquitoes within the state rather than brought in by an infected traveler alone. The Centers for Disease Control and Prevention says that kind of transmission is possible wherever Aedes mosquitoes are present.
So far in 2026, Florida has reported 149 dengue cases overall, according to the information cited by health officials.
Why dengue is called breakbone fever
Dengue is spread by the bite of an infected Aedes mosquito. The illness is found around the world and is especially common in tropical and subtropical regions. In the United States, the CDC says dengue has been reported in all states except Alaska.
The nickname breakbone fever reflects the intensity of the pain it can cause. Other symptoms include fever, headache, rash, nausea and vomiting. Symptoms usually begin within two weeks of a bite and typically last two to seven days, with most people recovering in about a week.
The CDC says about 1 in 20 people with dengue will develop severe dengue. That form can lead to shock, internal bleeding and death.
What the CDC says about risk in the United States
Although dengue is present in the United States, widespread transmission is considered uncommon. The CDC said the risk of broad spread remains low, even as limited local transmission has also been reported in Hawaii, Texas, Arizona and California.
Most U.S. cases are still linked to travelers who picked up the virus overseas. That makes local alerts important because they can help people and health departments focus on mosquito control and early symptom recognition when infections are identified close to home.
The CDC advises people to see a healthcare provider if they have dengue symptoms and live in or recently traveled to an area where dengue risk exists.
How residents can respond after an alert
Health warnings in Florida typically aim to slow mosquito exposure while officials monitor whether infections are spreading beyond the first few cases. In this case, the alerts in Hillsborough and Pinellas counties follow reports of locally acquired illness and reinforce the need for prevention during peak mosquito activity.
Residents are being urged to pay attention to fever, body aches, rash and other symptoms that could point to dengue, especially if they have been bitten by mosquitoes recently. Because dengue can become severe in a small number of cases, prompt medical attention matters when symptoms appear.
Officials also emphasize basic mosquito protection, since reducing bites is the main way to lower the chance of infection while local transmission is being investigated.
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