The Florida Department of Health estimated that the number of dengue cases from patients who traveled overseas would be high, but the total is more than quadrupled by what scientists had expected.
The state estimated that 2024 would bring 214 dengue travel cases. So far, the count is at 859.
“We were sounding some of the alarms about how we're going to see this spike in cases, both in Florida and beyond, and unfortunately, that held true,” said Dr. Michael Von Fricken a professor of environmental and global health at the University of Florida.
“You have to imagine we're really underreporting. We have suspected versus confirmed cases, and that's also going to be driving our importation as well,” he said.
Most cases have come from Latin America: Cuba, and Brazil, but the American territory of Puerto Rico was also a large dengue destination site. Latin American countries are experiencing historic dengue outbreaks. Travel-associated cases have increased in Florida with the rise of locally acquired cases.
“If we have an outbreak happening on our doorstep, you're going to expect to see that spilling over in positive cases returning from travel,” he said.
Florida has 74 locally transmitted cases for the year; two of those cases were in Orange County. They were the first two cases of the mosquito-borne disease documented in about 100 years. The county also observed about 45 travel-associated cases.
Dengue spreads in an area if a person who acquired dengue from outside the country is bitten by a mosquito that can carry it – such as the daytime biter Aedes aegypti.
Most travel cases were reported in South Florida, which accounted for 600 diagnoses. Central Florida has a little over 200 documented.
Likely fueling the high number of cases was a surge of travel and rising temperatures accompanied by a favorable El Nino cycle creating ideal conditions for mosquito reproduction.
“I think we're going to keep expecting to see more and more dengue each year as temperatures continue to rise,” Von Fricken said. “It's kind of creating this recipe for having a lower number of cases in the past, so you have a more susceptible population once it gets in. If you have enough mosquitoes to maintain it, it can really keep going.”
The fear is that the virus could become endemic to Florida with Aedes aegypti becoming more established in the state with an ideal climate and more people bringing the virus home.
Dengue, also known as bone break fever, has no cure. Often, patients are advised to drink water and rest while they endure painful symptoms for about a week.
“If you love those cruises and you're going out there, these things matter. Just be aware, wear bug spray,” Von Fricken said.
