Travel-related cases of dengue for June have exceeded what was expected for the year, according to the Florida Department of Health.
“The dengue cases concern me,” said Steve Harrison, manager of Orange County Mosquito Control. “I don’t think the public needs to be overconcerned right now, but dengue is on my radar.”
The health department published expectations for travel-associated cases of the mosquito-borne virus, expecting 214 cases for the year. As of Wednesday, travel cases were at 237.
In Orange County last year, 18 travelers were diagnosed with dengue. Halfway through this year, the county has 16, data shows. However, the county mosquito control team has responded to 21 cases.
“The official number is different because anytime a patient goes to a hospital and they're displaying symptoms of dengue, they're tested. Then the state will contact us with some of these suspected cases,” Harrison said. “But we don't really have the time to wait to see if it's confirmed.”
According to the World Health Organization, dengue case numbers are expected to increase around the world as global warming creates more suitable temperatures for mosquitoes carrying the virus.
Where is dengue spreading?
Most Florida cases have come from people visiting from Brazil and Cuba, which are both undergoing historically large outbreaks. Thirty-two percent of the travelers were from Cuba, and 24 percent were from Brazil, state data show.
According to the Centers for Disease Control and Prevention, dengue cases have risen dramatically across South America. In 2023, more than 4.6 million cases and 4,000 deaths were reported in the Americas region. As of Monday, there have been more than 9.7 million dengue cases.
On Tuesday, the CDC issued a Health Alert Network Health Advisory notifying health care providers and public health authorities of an increased risk of dengue in the U.S.
As for locally acquired dengue, Florida has recorded eight cases this year: six were from Miami-Dade County, one from Pasco County and a case in Hillsborough County was in late May.
Can dengue spread in Central Florida?
An increase in travel cases combined with hotter-than-average temperatures have Harrison concerned about it being the perfect environment for more locally acquired cases.
The mosquito responsible for carrying dengue is known as Aedes egyptide.
“The hotter temperatures speed up the process going from egg to adult. It could shorten the duration, which now you have more adult mosquitoes in that area that could potentially bite somebody,” Harrison said.
Mosquito control has stepped up its efforts to stop any potential spread of locally acquired cases by setting up barrier treatments to kill mosquitoes in areas where people who have been diagnosed spent time.
“You have a person that travels here, they're sick, they're shedding virus. If a mosquito were to bite them, they could then take in the virus, amplify it and then start spreading it," Harrison said.
The calls have been a strain on mosquito control, which has been forced to step up its efforts to reduce the risk of local mosquitoes harboring the virus. Aedes egyptide is particularly difficult to kill since it behaves differently than other mosquitoes. Aedes egyptide, also known as the yellow fever mosquito, has modified its behavior to zone in on its primary source of food – humans.
“Aedes egyptide is pretty unique as a daytime biter,” Harrison said. “They're well-adapted to living with people. They've kind of learned our habits. They know that we're primarily up during the day, we're hanging out on the back porch on the weekend.”
What is mosquito control doing about it?
“It’s very labor intensive, you know, it's not uncommon to have 100 or 110-plus homes within that 600-foot radius that we have to go door to door, do inspections, do treatments, do education,” Harrison said.
To keep up, mosquito control increased its efforts of knocking down possible dengue sites during the day. The team is unable to rely on nighttime truck sprays as it would with most other mosquitoes due to Aedes egyptide's diurnal habits.
Mosquito control has stepped up its efforts to stop any potential spread of locally acquired cases by setting up barriers to kill mosquitoes in areas where people who have been diagnosed spent time.
What residents should do
Residents can help mosquito control keep numbers down by tipping and tossing still water on their properties.
“If they can do that, that will cut down you know the competent vectors and could spread this disease,” Harrison said. “We want people to be on guard again, don't panic. Don't be overly concerned. If mosquitoes are active, obviously cover your skin with some clothing or some insect repellent.”
Symptoms of dengue
Symptoms usually last two to seven days. The most common symptom of dengue is fever but also includes the following:
- Aches and pains (eye pain, typically behind the eyes, muscle, joint, or bone pain)
- Nausea, vomiting
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