- The CDC issued an advisory ahead of spring and summer travel to remain vigilant as cases of dengue fever are expected to rise in the U.S. and globally.
- The Aedes mosquito transmits dengue, and there is no cure. Rare, severe cases can be life threatening.
- As global temperatures rise, experts say the mosquitoes’ territory will expand, causing further increases in dengue cases.
As cases of dengue fever rise among U.S. travelers, the Centers for Disease Control and Prevention (CDC) issued an
Dengue fever cases among U.S. travelers reached record-breaking levels in 2024, with 3,484 cases reported. Compared to the year prior, this marked an 84% increase.
“This trend is expected to continue with increased dengue activity in endemic areas in 2025,” the CDC advisory states.
Transmission of dengue fever remains high worldwide and in some parts of the United States.
High levels of activity have also been reported in the Americas, the U.S. territories of Puerto Rico, and the U.S. Virgin Islands. Dengue fever cases have been rising over the past five years in these regions, according to the
More than 7.6 million dengue fever cases were reported in 2024, compared to 4.6 million in 2023. Around 16,000 cases were considered severe and over 3,000 resulted in death.
Last spring, Puerto Rico declared a public health emergency amid rising dengue cases, which remains in effect. In 2024, 6,291 cases were reported. The U.S. Virgin Islands declared a dengue fever outbreak in August 2024 that also remains in effect.
In the U.S. Virgin Islands, 208 cases were reported in 2024, with 30 cases confirmed in 2025. On the U.S. mainland, local transmission of dengue fever was reported in 2024 in California, Florida, and Texas,
There are no vaccines against dengue fever for anyone who has not previously had a dengue infection.
While a
There are four strains of dengue, all carried by the Aedes mosquito, which generally lives in tropical and subtropical regions.
The hotter and wetter months of the year are typically when cases of dengue peak, putting travelers at a higher risk of infection from the virus. As global temperatures rise, the CDC says dengue cases will most likely continue to increase each year.
Symptoms of dengue fever infection depend on the severity of the disease. Around
Mild symptoms may include a sudden fever of around
Symptoms usually last between
Between
In this instance, the fever typically falls to 99.5 to 100.4°F (37.5 to 38°C). Anywhere between a day and a week later, additional symptoms include:
- abdominal pain or tenderness
- vomiting at least three times in 24 hours
- bleeding from the nose or gums
- vomiting blood
- blood in the stool
- fatigue
- feeling restless or irritable
changes in temperatureTrusted Source from very hot to very cold- cold, clammy skin
- a weak and rapid pulse
- a reduced difference between systolic and diastolic blood pressure
There are currently four known strains of the Dengue virus, and there is no cure, so essentially, anyone bitten by a mosquito carrying the virus could catch it.
David Cutler, MD, board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, told Healthline those at highest risk of severe dengue, which can result in death, include:
- infants under 1
- pregnant people
- adults over 65
- people with underlying medical conditions (i.e., hypertension, diabetes, asthma, chronic kidney disease, chronic liver disease, peptic ulcer disease or other gastritis, obesity, or anyone receiving anticoagulant medications)
“Treating dengue requires supportive care as there is no cure for this disease. Monitoring fever, hydration status and blood tests are important for detecting any signs of the disease becoming critical. Controlling fever, preventing dehydration, and restricting disease spread through mosquito control are the most important measures to managing dengue,” Cutler said.
“Preventing [the] spread of disease, especially in young children, requires that everyone sleep under a mosquito net. Insect repellents are also an important preventive measure. Emptying and cleaning standing water containers deprives mosquitoes of places to breed. Screens on windows and doors will help prevent mosquitoes from entering the home,” he explained.
Jessica Tuan, MD, an infectious disease expert with Yale New Haven Hospital in Connecticut, told Healthline that traveling to areas where dengue is most prominent also puts people at risk for exposure.
“Those who have traveled to dengue-endemic areas are at highest risk for acquiring dengue. Dengue is endemic in tropical areas including, Africa, the Americas, Southeast Asia, Eastern Mediterranean region, and the Western Pacific. Areas with frequent or continuous dengue transmission include Puerto Rico, U.S. Virgin Islands, American Samoa, Republic of Marshall Islands, Federated States of Micronesia, Republic of Palau,” Tuan said.
“Take measures to prevent mosquito bites, including using mosquito repellent, for those traveling to or living in dengue-endemic areas. The Advisory Committee on Immunization Practices recommends the dengue vaccine, Dengvaxia, for children 9 to 16 years old with prior laboratory-confirmed dengue virus infection and living in areas with frequent or continuous dengue transmission,” she added.
James Shepherd, MD, an infectious diseases specialist at Yale Medicine, told Healthline that the dengue virus cannot mutate like other viruses like COVID-19 has because there is no cure for it.
“As there is no treatment, there is no selection for treatment resistance. Is that a possibility in the near future? Not without the development of new treatments to select resistance. There may be selection by human and mosquito host factors, and evolution of viral pathogens is a natural process, but there are no significant changes in the virus correlating with human disease that I am aware of,” Shepherd said.
Shepherd added that as the CDC expects more cases of dengue due to rising global temperatures, finding some sort of antiviral medication might be possible.
“As Aedes mosquitoes spread northwards with rising global temperatures dengue outbreaks are becoming more common in more temperate, richer countries and this presents a greater incentive for drug companies to spend on new antiviral drug development,” Shepherd said.