Florida is battling what experts believe is America’s largest outbreak of mosquito-borne dengue fever in more than 80 years.
The Florida Department of Health recorded another 72 locally acquired cases of the disease last week, taking its total to 368 locally acquired cases so far.
Federal health officials said their data on dengue outbreaks was limited, but that based on available information from state health departments the tally for this outbreak exceeds that for any other since 1945.
The previous largest outbreak was in Hawaii, according to official data, where 264 locally-acquired cases were recorded over six months in 2015 and 2016.
Dengue fever is often called ‘breakbone fever’ because patients who get sick with the virus typically develop a sudden high fever along with a pounding headache, pain behind the eyes and deep aches in the muscles, joints and bones.
The US records cases every year. These are normally linked to international travel, or when someone returns to the country with the infection, but in recent years more cases have been locally acquired.
In the continental US overall, there have been 995 dengue fever cases recorded this year, including 626 travel-associated infections and 369 that were locally acquired, including the outbreak in Florida and one case in Virginia.
A Centers for Disease Control and Prevention (CDC) report from earlier this year showed there was a 359 percent rise in average annual dengue fever cases in the US in 2024 compared to the 2010-2023 annual average.
Dengue fever spreads through the bite of infected Aedes mosquitoes, mainly the Aedes aegypti (pictured above), a species commonly found in Florida
Florida has recorded 656 cases of dengue fever overall this year, of which 288 were travel-associated, or about 40 percent.
For locally-acquired cases in Florida, Hillsborough County, home to Tampa, is at the epicenter, having recorded 310 locally-acquired infections, alongside Pinellas County, in the Tampa metropolitan area, which has recorded 37 cases.
Miami-Dade County has recorded nine cases, while Orange County, which includes Orlando, has recorded five and Pasco County, outside Tampa, has recorded four.
Polk County, between Tampa and Orlando, and Palm Beach County and Broward County on Florida’s east coast, have each recorded one case.
It was not clear how the virus had entered Florida, but this can happen if someone who is infected with the disease returns from abroad and is bitten by a mosquito. That mosquito will then become infected and can transmit the disease to another person that it bites.
Among those who have been infected in the outbreak in Florida is Maurice Kurtz, a 73-year-old from St Petersburg, who said the disease made him feel like he had been hit by a car.
His temperature spiked to 101F, and he was incredibly fatigued even from just a walk around the block.
‘I went around the block and, oh, I ached so much,’ he told CIDRAP News. ‘This was way beyond the tightness and aching I get from the most strenuous workouts I’ve ever done.’
Over the next two days, he slept for 16 hours, which was unusual for the normally active swimmer, biker and runner. He also noted that a few days earlier, he noticed itchy, tiny red spots on his legs.
Kurtz tested negative for flu and COVID, and when he asked doctors for a dengue fever test, they at first insisted cases were mostly found further up north, in Hillsborough County.
But when Kurtz said that he had visited Tampa the day before he fell ill, he finally received a blood test that came back positive for dengue fever.
Kurtz has made a recovery, though he still struggles with fatigue and getting back to his active lifestyle.
‘I just got a mosquito bite and I’m recovering from this disease, which has a reputation of being this rare tropical thing,’ he said.
‘The likelihood of you getting it is very, very slim. But it could happen to you – and in [my] case, it did.’
Dengue fever was nearly eradicated in the US in the 1970s amid a campaign to wipe out the Aedes aegypti mosquito, identified by the white bands on its legs, which carries the virus.
After that campaign was abandoned, however, the mosquito – and dengue fever – have repeatedly triggered sporadic outbreaks, particularly in Florida.
The above map shows all countries for which the CDC has issued a level 1 travel advisory due to the spread of dengue fever
Dengue fever often causes an asymptomatic infection, but in some patients it can trigger life-threatening internal bleeding, respiratory distress and heart failure.
It can also lead to shock and organ failure, especially of the liver, brain and heart.
Health officials say about 40 to 80 percent of people infected with dengue fever do not develop any symptoms, but if symptoms do develop, they appear abruptly about five to seven days after infection.
Warning signs include a fever above 100F (38C), severe headache, pain behind the eyes, bone, joint or muscle pain, and bleeding in the gums.
Some patients also develop redness of the skin on the face within the first 24 to 48 hours of symptoms emerging.
In severe cases, patients may also suffer from severe abdominal pain, persistent vomiting and lethargy.
Patients may also develop dengue shock syndrome, a condition where severe bleeding leads to a rapid drop in blood pressure and causes the body to go into shock.
Children under five, adults over 65 and pregnant women are considered to be most at risk from the virus.
There is no specific cure for dengue fever and treatment consists of supportive care and therapies to manage symptoms and complications.
Doctors recommend patients with mild symptoms drink plenty of fluids and take Tylenol to ease pain.
In severe cases, patients may be admitted to the hospital for supportive care, an IV, blood pressure monitoring and a transfusion to replace lost blood.
To protect against dengue fever, there is a three-dose vaccine available, which is recommended for children ages nine to 16 years who have previously been confirmed to have a dengue infection. It slashes the risk of a symptomatic infection by about 80 percent.
Dengue fever can also be prevented by using insect repellent and long, protective clothing to avoid mosquito bites. Eliminating standing water by dumping it out of buckets, pet dishes and roof gutters also prevents mosquitoes from laying eggs.
Additionally, the CDC recommends using screens on windows and doors or staying in air-conditioned rooms.
