CDC issues global dengue alert as Americas surge

A new global alert on dengue from the United States Centers for Disease Control and Prevention is drawing fresh attention to record case numbers across the Americas and the growing risk to international travelers heading for the region’s beaches, cities, and eco-tourism hotspots.

Record-breaking dengue seasons reshape the travel risk map

Publicly available CDC data show that worldwide dengue infections reached an estimated 14.1 million cases in 2024, with approximately 13 million reported in the Americas alone, a sharp increase of around 8 million compared with the previous year. Regional surveillance compiled by the Pan American Health Organization indicates that 2024 was the highest year on record for dengue in the Americas, with more than 13 million suspected cases and thousands of deaths reported across 50 countries and territories.

Although 2025 brought some respite, PAHO reports a substantial 66 percent drop in cases compared with 2024, the organization still counted more than 4.4 million suspected infections in the Americas that year, a level consistent with a major regional epidemic rather than a return to pre-surge norms. Recent updates from early 2026 continue to classify dengue as a significant public health problem in the hemisphere, with several countries entering a new transmission season against a backdrop of high baseline circulation.

CDC surveillance summarized in its Morbidity and Mortality Weekly Report describes 2024 as a pivotal year for travelers, with dengue diagnoses among residents of the contiguous United States and the District of Columbia rising 359 percent compared with the 2010 to 2023 annual average. Nearly all of those infections were linked to international travel, underscoring how closely the domestic picture is tied to what is happening in popular destinations throughout Latin America and the Caribbean.

For travelers, the result is a risk landscape that looks markedly different from just a few years ago. Locations once considered low to moderate risk for short-term visitors now report intense seasonal transmission, and health agencies stress that there is no longer a clear dividing line between “high” and “low” dengue destinations across much of the tropical and subtropical Americas.

Key hotspots across Latin America and the Caribbean

Regional situation reports point to particularly high transmission in parts of the Southern Cone, the Andean region, Central America, and the Caribbean during the 2024 and 2025 seasons. Argentina, Paraguay, Brazil, Bolivia, and several Caribbean islands reported historic or near-historic outbreaks in 2024, with some countries recording case counts many times higher than previous peaks. Argentina’s 2024 season, for example, saw record weekly tallies and unusually early transmission, coinciding with sustained heat and heavy rainfall.

Caribbean destinations that feature prominently on winter tourism itineraries have also seen sustained dengue activity. Data compiled by PAHO show large outbreaks in the Dominican Republic, Martinique, Guadeloupe, and other island territories during the 2024 surge. In many of these locations, dengue transmission did not fully subside between traditional peak seasons, leaving health systems and tourism operators planning for more prolonged periods of heightened risk.

Central American nations including Honduras, El Salvador, Costa Rica, and Guatemala have reported recurrent waves of dengue cases through 2024 and 2025, intersecting at times with other mosquito-borne infections such as chikungunya and Zika. According to regional bulletins, several of these countries are experiencing the simultaneous circulation of all four known dengue virus serotypes, a pattern associated with an elevated probability of severe disease because repeat infection with a different serotype can trigger a more dangerous immune response.

Travel planners note that these shifts are not confined to a single city or resort corridor. Instead, transmission has been documented in coastal resorts, inland capitals, mid-sized provincial cities, and rural areas alike. For visitors, the practical takeaway is that dengue precautions now warrant serious consideration for a broad range of itineraries, from rainforest lodges in Costa Rica to wine routes in northern Argentina.

United States lens: travel-related cases and emerging local outbreaks

While the vast majority of infections still occur in tropical and subtropical countries, the United States has seen a notable ripple effect from the regional surge. CDC figures show that in 2024, travel-associated dengue cases among residents of the mainland United States climbed sharply, mirroring historic activity in the Americas and aligning with increased travel to outbreak-affected destinations.

At the same time, reports indicate that locally acquired cases have become more frequent in parts of the United States where the Aedes aegypti mosquito is established. Florida has experienced its largest dengue outbreaks in decades, according to recent coverage from national news outlets that cite state health department data, including clusters in the Tampa Bay region and the Florida Keys. Puerto Rico, a major Caribbean gateway for U.S. travelers, continues to record substantial numbers of infections in some seasons, contributing to the national case tally.

CDC’s Health Alert Network advisory on dengue, issued at the height of the 2024 surge, emphasized that international travel patterns, combined with warm conditions favorable to mosquitoes in parts of the southern United States, create ongoing opportunities for the virus to spread to local mosquito populations. Although intensive mosquito control has limited the scale of most outbreaks to date, the advisory framed dengue as an increasingly persistent seasonal concern rather than a rare import.

For travelers departing from or returning to the United States, this evolving picture has practical implications. Travel medicine clinics now routinely review dengue risks alongside more established concerns such as malaria or typhoid in pre-trip consultations, particularly for itineraries that combine multiple countries or include extended stays with friends and relatives in affected regions.

Drivers behind the surge: climate, cities, and mobility

Global and regional assessments from the World Health Organization identify several intertwined factors behind the rising dengue curve. Rapid urbanization in the tropics has produced dense neighborhoods with intermittent water supply and abundant non-biodegradable waste, providing ideal breeding sites for Aedes mosquitoes in water-filled containers, tanks, and discarded items. Many of the hardest-hit urban areas in Latin America and the Caribbean combine high population density with aging infrastructure and limited mosquito control coverage.

Climate variability and long-term warming trends are also playing a growing role. Hotter average temperatures, prolonged heat waves, and shifts in rainfall patterns extend the viable season for mosquito activity and speed up viral replication within the mosquito. Researchers analyzing the 2024 Southern Cone outbreaks noted that unusually high temperatures and heavy rains arrived weeks earlier than in past years, helping drive earlier and more intense transmission.

International mobility amplifies these environmental trends. Commercial flight connections link dengue-endemic cities to major global hubs, and record numbers of passengers to and from Latin America and the Caribbean in recent years have increased the probability that infected travelers will carry the virus across borders. WHO’s recent global dengue update highlights expanding air travel and trade as central to the spread of both mosquitoes and viruses into new areas, including higher-latitude zones where competent vectors are already present.

On top of these drivers, virologic patterns are compounding the risk. Surveillance data from PAHO and WHO show concurrent circulation of multiple dengue serotypes across much of the Americas. When a population is exposed over time to different serotypes, the overall proportion of people at risk for severe outcomes can climb, because a second infection with a new serotype is more likely to progress to severe dengue than a first infection.

What the CDC alert means for travelers planning trips now

The CDC’s global dengue alert aims to translate these complex epidemiological trends into practical guidance for travelers. Publicly available travel health notices recommend that prospective visitors to affected areas review the latest country-level situation summaries before departure, paying close attention to seasonal peaks that often coincide with local rainy seasons. For itineraries to Latin America and the Caribbean between roughly November and May, that typically means heightened vigilance in many popular sun-and-sand destinations.

Travel health resources stress that, in the absence of widely available dengue vaccines for most international travelers, personal protection against mosquito bites remains the primary line of defense. Recommendations include using Environmental Protection Agency–registered insect repellents containing DEET, picaridin, IR3535, or oil of lemon eucalyptus, wearing loose-fitting long sleeves and long trousers in mosquito-prone areas, and choosing accommodations with air conditioning or intact window and door screens.

The alert also encourages travelers returning from outbreak-affected countries to stay alert to symptoms such as high fever, headache, severe muscle or joint pain, nausea, vomiting, or a rash within two weeks of travel. Health agencies advise that anyone with warning signs like abdominal pain, persistent vomiting, bleeding, or difficulty breathing seek urgent medical care, and note that early clinical monitoring can reduce the risk of severe complications.

For the travel industry, the evolving dengue situation is prompting a more explicit integration of mosquito-borne disease information into pre-trip communications, tour briefings, and hotel welcome materials. Some destinations and operators are highlighting local vector control campaigns, water management efforts, and guest-facing measures such as screened patios or on-site repellent dispensers, as they seek to reassure visitors while acknowledging that dengue risk in the Americas has become a long-term reality rather than a short-lived spike.