CDC issues global dengue alert as Americas surge

The U.S. Centers for Disease Control and Prevention has issued a global health advisory on dengue, warning travelers of a sharply elevated risk as record outbreaks in the Americas and other regions reshape how and where people plan their trips.

Record dengue numbers reshape the travel risk map

According to publicly available data from the World Health Organization, 2024 marked the highest global dengue burden ever recorded, with cases reported in more than 100 countries and an estimated 14.6 million infections worldwide. Health surveillance reports indicate that over 13 million of those cases occurred in the Region of the Americas, making the hemisphere the current epicenter of transmission.

Regional bulletins from the Pan American Health Organization show that countries including Brazil, Argentina, Mexico, Colombia, Paraguay and Peru have accounted for the majority of reported infections. Brazil alone has reported more than 10 million cases for 2024, an unprecedented figure that has driven the regional surge and drawn particular attention from travel health specialists watching major gateways such as Rio de Janeiro, São Paulo and Brasília.

Although total case counts in the Americas decreased in 2025 compared with the historic peak in 2024, PAHO’s 2025 reporting still records more than 4.4 million infections, indicating that transmission remains well above pre-2023 levels. For travelers, this means dengue risk in much of Latin America and the Caribbean is no longer limited to sporadic outbreaks but reflects sustained, high levels of circulation across multiple seasons.

The CDC advisory draws a direct link between this regional picture and travel-associated risk, noting that large epidemics in popular destinations significantly increase the chance that visitors will be exposed, and that infections imported by travelers can seed limited local transmission in areas that host competent mosquito vectors.

What the CDC alert says and who it targets

In its Health Alert Network advisory, the CDC highlights an increased risk of dengue infections for U.S. residents during and after travel, citing a steep rise in both travel-associated and locally acquired cases reported in 2024. Surveillance summaries show that the United States recorded 3,798 dengue infections that year, a more than threefold increase over the average annual total from 2010 to 2023, with nearly all linked to recent international travel.

The advisory emphasizes that this upturn closely tracks the surge of dengue in the Americas, particularly in Latin America and the Caribbean. Publicly available analyses indicate that more than 9.7 million cases were reported in the region between January 1 and June 24, 2024 alone, roughly twice the total for all of 2023. The CDC notice frames the current situation as part of a wider, multi-year upsurge in dengue activity that began in 2023 and has continued through 2025 and 2026.

The alert is directed at both the general public and health professionals, but it has specific implications for travelers, tour operators and airlines. The CDC encourages clinicians to routinely ask about recent travel when evaluating febrile illness, while travel planners are urged to consider dengue activity when advising customers on itineraries, trip timing and on-the-ground precautions in destinations with active transmission.

Notably, the advisory does not recommend broad travel restrictions. Instead, it focuses on risk awareness and prevention, particularly for travelers visiting family and friends in dengue-endemic countries, a group that surveillance data show is disproportionately represented among severe cases and hospitalizations.

Hotspot destinations: from Caribbean beaches to U.S. sun belts

For international travelers from the United States, the areas of most immediate concern include many of the region’s most popular leisure destinations. Tourism-heavy countries such as Brazil, Mexico, Colombia, Peru, the Dominican Republic and several Central American nations have all reported substantial dengue activity since 2024, according to PAHO’s regional surveillance platform.

On a more local scale, some parts of the continental United States have faced their own dengue challenges. Reports compiled by state health departments and national media describe one of Florida’s largest dengue outbreaks in decades, with hundreds of locally acquired cases and at least one related death. While the overall risk for visitors remains much lower than in many tropical countries, the presence of sustained local transmission in parts of Florida, Texas and Arizona has prompted renewed attention to mosquito control and traveler messaging within the country.

Elsewhere in the Americas, major urban centers from Buenos Aires to Mexico City and coastal resort hubs from Cancún to Rio de Janeiro have all seen periods of elevated dengue transmission during the past three years. For travelers, the pattern means that dengue risk can be significant in both big cities and smaller resort communities, not just in rural or jungle areas, and that risk can shift quickly from one destination to another within a single season.

European and Asian travel markets are also watching the trend. WHO’s wider dengue upsurge assessment notes increased transmission in parts of Southeast Asia and the Western Pacific, adding further complexity for long-haul travelers planning multi-country trips that might combine Latin American and Asian itineraries within a single journey.

How climate and urbanization are amplifying dengue risk

Global health analyses link the current dengue surge to a combination of environmental and social drivers. WHO fact sheets and situation reports describe an eightfold increase in global dengue incidence between 2000 and 2019, a trend that has continued upward as climate change, rapid urbanization and increased human mobility reshape mosquito habitats and human exposure patterns.

Rising temperatures and more intense rainfall events expand the geographic range and breeding season of Aedes aegypti and Aedes albopictus mosquitoes, the main dengue vectors. Modeling studies cited in European climate and health reports suggest that areas previously unsuitable for these mosquitoes, including parts of southern Europe and higher-altitude zones in the Americas, are becoming increasingly conducive to seasonal transmission.

At the same time, unplanned urban growth in many low and middle income countries has created densely populated neighborhoods with limited access to reliable piped water and waste management. These conditions favor water storage in open containers and accumulation of small amounts of standing water, both of which provide ideal breeding sites for Aedes mosquitoes. Health agencies warn that such environmental shifts can transform dengue from a sporadic threat into a regular feature of the urban health landscape.

International travel acts as an accelerant within this context. Travelers can carry the virus from high-incidence countries to new locations where competent mosquitoes are present, occasionally triggering local outbreaks. The CDC advisory notes that travel-associated cases were the overwhelming driver of the 2024 increase in U.S. dengue reports, underscoring how tourism and business travel now shape dengue dynamics far beyond traditionally endemic zones.

What travelers can do before and during trips

For travelers, the CDC alert effectively raises dengue to the same level of attention as other well-known travel-related infections. Public guidance emphasizes several practical steps: checking country-specific dengue activity on official travel health pages before booking or departing, discussing individual risk factors with a health provider, and considering itinerary adjustments during peak transmission periods in the most heavily affected locations.

Because there is no widely available antiviral treatment for dengue, prevention centers on avoiding mosquito bites. Travel health advice highlights the use of EPA-registered insect repellents containing active ingredients such as DEET, picaridin or IR3535; wearing long sleeves and long trousers in areas with active mosquitoes; and choosing accommodations with effective window screens or air conditioning. In destinations where open-air lodging is common, the use of bed nets and screened verandas can provide an additional layer of protection.

Some countries in the Americas have begun introducing dengue vaccines for specific age groups or populations, but access remains limited and policies vary widely between jurisdictions. Travelers are encouraged to consult up-to-date official guidance for their destination, as eligibility criteria, product availability and recommendations can change over time and may not apply to short-term visitors.

The CDC alert also reinforces a key message for returning travelers: anyone who develops fever, headache, muscle or joint pain, rash or unexplained bleeding within two weeks of visiting a dengue-affected area should seek medical care and promptly mention their recent travel history. Early recognition can improve clinical management and reduce the risk of severe disease, while also helping public health agencies track and respond to emerging clusters that may affect future travelers.