The Tampa Bay region is experiencing more local cases of dengue fever than usual this year.
The Florida Department of Health reported eight cases in Hillsborough County and two in Pinellas County so far, and both are on a mosquito-borne illness alert.
For Pinellas, it's the first case of locally acquired dengue in over 15 years, according to data from the CDC.
"Pinellas doesn't have any modern history of having dengue in the county," said Alyssa Berro, mosquito control manager for Pinellas County. "So this is one of those cases [where] somebody has returned from somewhere they got bit. And then got bit by our mosquitoes which then started the transmission in this area."
Symptoms of dengue typically appear 15 days after being bitten by an infected mosquito.
The illness, also referred to as bone-break fever, can come with joint and muscle pain. Other symptoms include pain behind the eyes, nausea, vomiting and rash.
Local versus travel-associated
Dengue is not what experts call endemic, or regularly found, in the state.
Typically, people will contract dengue while traveling to other countries, rather than getting bit by an infected mosquito in the Tampa Bay area.
Dengue is not contagious between humans, but it can spread if a mosquito bites someone with the illness and becomes a carrier.
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It can then spread the disease by biting others or breeding more dengue-carrying mosquitos.
Between 2010 to 2025, Hillsborough County reported 277 dengue cases due to travel, and nine locally acquired cases.
The eight locally acquired cases for this year were reported within the last two weeks.
"And that's what makes this such a big change, is that it is going around in the mosquitoes in our county," said Gabriela Henderson, community relations coordinator for Hillsborough County Mosquito Management.
Mosquito treatment
Efforts to control the spread are underway.
Mosquito control for both counties are treating areas by truck and helicopter aerial sprays.
Pinellas and Hillsborough county residents can check which neighborhoods have been treated online.
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Technicians are also visiting homes and businesses to treat mosquito-prone areas by hand.
County health officials are encouraging residents to get rid of any standing water around their homes.
"They like to lay their eggs near humans in things like buckets, toys we might leave outside in the rain, tarps, planters," said Henderson. "Anything that can hold even just a bottle cap-sized amount of water is enough for mosquitoes to go through their whole life cycle."
Henderson said tires are a common breeding ground for mosquitos since they tend to hold water.
The mosquito control teams also manage a number of mosquito traps located across each county.
These BG traps or biogent traps, have components that mimic human scent and emit carbon dioxide to lure in adult mosquitos.
The trapped mosquitos are then taken back to the lab, where they're frozen and killed. The female mosquitoes, which are the only mosquitoes that bite humans and animals, are separated and sent to a lab that tests for dengue.
Henderson said one mosquito from Hillsborough so far has come back positive.
Protect yourself
The breed of mosquitoes carrying dengue are the aedes aegypti and aedes albopictus.
These dengue-carrying mosquitoes will bite during the daytime, not just in the evening and tend to stay low to the ground. That makes them harder to avoid and detect.
Berro said residents should check their yards once a week for standing water.
She recommended people wear light-colored clothing that covers the legs and arms when they go outside, and to use EPA-approved insect repellent that contains DEET, IR3535, picaridin or oil of lemon eucalyptus.
"We call those the three D's: to dump, dress, and defend," said Berro.
