Florida is confronting an unusual rise in dengue fever, with at least 252 cases and one death reported this year, according to data from the Florida Department of Health . The increase in cases is drawing attention to a disease many Americans may not be aware of—and that can occasionally become life-threatening. Here’s what everyone should know about dengue fever.

What Is Dengue Fever And How Do You Get It?

Dengue is a mosquito-borne viral illness that is transmitted through the bite of an infected mosquito, often the Aedes aegypti mosquito. Most commonly, the mosquito bites an individual that has the dengue virus, becomes infected and then is able to infect other humans by biting them.

This disease is not usually spread person-to-person. Although dengue fever is not endemic to any state in the United States, the mosquito that causes dengue fever is usually present in some states, including Florida.

How Common Is Dengue In The United States?

Historically, dengue has been relatively uncommon in the U.S. According to CDC data, between 2010 and 2023, an average of 828 dengue cases were reported annually among residents in the U.S.

However, in 2024, that number increased to 3,798 cases, with 97% of those cases associated with travel. During that year, Florida accounted for over 1,000 cases, with 85 locally acquired infections.

What Symptoms Should You Watch For?

About three in four individuals with dengue will have no symptoms. Most people who do develop symptoms will get them about five to seven days after being infected by the competent mosquito. Patients typically report getting a sudden fever, headaches, pain behind the eyes, muscular or bone pain, nausea, vomiting and sometimes a rash. These symptoms last for several days to about a week.

In 5% of cases, some patients can develop severe dengue, which leads to internal bleeding and can be life-threatening with shock and organ failure. These patients may have severe abdominal pain, bleeding from the nose, blood in the stool and extreme fatigue. They require immediate medical attention to avoid dehydration and multi-organ failure.

How Is Dengue Diagnosed And Treated?

The infection can be difficult to diagnose and recognize because symptoms resemble the flu. However, if an appropriate history of a mosquito bite is given, a blood test can usually confirm the diagnosis.

No specific treatment is available that targets the virus that causes dengue fever. That is why treatment is usually supportive and consists of resting, getting adequate fluids to prevent dehydration and taking medications to relieve fever and pain. Those with severe dengue should be hospitalized and monitored for signs of dehydration and bleeding.

There are a couple of possible explanations for the recent rise of dengue fever in the U.S. Increased globalization and travel allows cases to be imported from countries where dengue is endemic. In addition, research also suggests climate change causing warmer weather, increased rainfall and humidity could expand the geographic range for mosquitos to infect humans in America, for longer periods of time, in warmer months.

Finally, some states like Florida have ideal conditions, such as warm weather and standing water, that can allow mosquitos to reproduce and survive.

The best way to prevent getting dengue infection is by decreasing your risk of being bitten by the causative mosquito. Evidence-based strategies include wearing long-sleeve shirts and pants, using EPA-approved insect repellents on your body and clothes and eliminating standing water around your home and residence. The mosquitos that cause dengue fever breed and reproduce in areas of standing water, which would include buckets, pet bowls, gutters and flowerpots.

Dengue is no longer simply a disease Americans encounter when traveling abroad. Local transmission can occur in the U.S., and recognizing the symptoms early may be critical in preventing severe disease.