CDC issues global dengue alert as Americas surge

The US Centers for Disease Control and Prevention has updated a global dengue travel notice after sustained surges across the Americas, prompting fresh guidance for international travelers as millions of infections reshape risk maps from Mexico to southern Brazil.

Global notice reflects record dengue activity

According to publicly available CDC travel health information, dengue is now the subject of a standing Global Dengue travel notice at Level 1, the lowest of four CDC travel advisory tiers but one that formally recognizes year-round transmission and elevated activity in multiple regions. The notice, first posted in June 2024 and updated regularly, was most recently revised on November 10, 2026, and emphasizes that outbreaks tend to recur every two to five years in many destinations.

CDC materials describe dengue as a viral disease spread by Aedes mosquitoes, which bite during the day and thrive in urban environments. The global notice highlights that a growing list of countries are reporting higher than usual numbers of cases, or that health surveillance systems in the United States are detecting a higher than expected number of dengue infections among returning travelers from those areas.

Separate CDC surveillance summaries indicate that worldwide dengue cases climbed sharply over the past five years, with especially steep increases in the Americas. Travel medicine references such as the CDC Yellow Book point to a parallel rise in travel associated dengue among US residents, reinforcing why a broad, sustained travel notice now covers dengue risk rather than short, country specific advisories.

Within the CDC travel health framework, a Level 1 notice does not advise against travel but signals that travelers should be aware of a defined health risk and follow specified protective measures. For dengue, those measures focus heavily on mosquito bite prevention and early recognition of symptoms after travel.

Americas emerge as epicenter of recent surge

Regional data compiled by the Pan American Health Organization and summarized in multiple public reports show that the Americas have experienced unprecedented dengue activity since 2024. One CDC analysis of 2024 case reports from the region stated that countries in the Americas surpassed all previous annual records, with more than 9.7 million cases recorded by late June 2024 alone, roughly double the total for all of 2023.

Subsequent tallies for 2024 published by regional and global surveillance platforms describe more than 13 million suspected dengue cases across the Americas that year, followed by more than 4 million additional suspected infections in 2025. Although the 2025 total represented a decline from the peak, public health reviews from mid 2025 still characterized transmission across Latin America and the Caribbean as intense, with all four dengue virus serotypes co circulating in many countries.

Country specific reports highlight particularly heavy impacts in Brazil, Argentina, Paraguay and several Andean and Central American nations, where large urban populations, favorable mosquito habitats and climate variability have combined to fuel multiple, overlapping outbreaks. Caribbean destinations that are popular with US and European tourists, including Puerto Rico, the Dominican Republic and several Lesser Antilles islands, also reported sustained activity.

CDC technical updates issued in 2024 and 2025 describe these trends as part of a broader pattern of rising arboviral disease risk in the Americas, with dengue now considered a leading cause of febrile illness in travelers returning from tropical and subtropical parts of the region.

Changing risk profile for US travelers

Surveillance summaries released through CDC publications indicate that dengue is increasingly affecting US residents who travel to or live in areas with frequent or continuous transmission. One analysis of 2024 reports from the 50 US states and the District of Columbia documented 3,798 dengue cases in that year alone, an increase of more than 350 percent compared with the annual average from 2010 through 2023. More than 97 percent of those infections were linked to travel, with the remainder acquired locally in areas such as Florida, Texas, Arizona and California where Aedes mosquitoes are established.

Further updates circulated through CDC’s Health Alert Network in 2025 noted that locally acquired dengue continued to appear in limited parts of the continental United States, while Puerto Rico and some other US territories reported sustained outbreaks. Public information from state health departments and national media coverage in 2025 and 2026 also documented a growing number of locally transmitted cases in Florida, leading to the state’s largest dengue outbreak in decades.

For international travelers, CDC guidance stresses that risk varies sharply by destination. A current CDC dengue risk map lists much of tropical Latin America and the Caribbean as areas of frequent or continuous transmission, including Mexico, most of Central America, large sections of northern and central South America, and many island territories. By contrast, Canada, most of the continental United States and southern regions of South America such as Chile and southern Argentina are described as having no evidence of sustained dengue transmission.

Travel medicine specialists writing in the CDC Yellow Book note that short term visitors can still face substantial exposure during high season outbreaks, particularly in urban centers and resort areas where mosquitoes breed in standing water around homes, hotels and construction sites.

What the global notice means for trip planning

Although the current CDC notice classifies dengue as a Level 1 risk globally, practical implications for travelers can be significant. The advisory states that people heading to affected destinations should focus on avoiding mosquito bites by using Environmental Protection Agency registered insect repellents, wearing long sleeves and long pants when possible, and staying in accommodations with air conditioning or intact window and door screens.

CDC guidance emphasizes that travelers who develop fever, headache, eye pain, muscle or joint aches, nausea or a rash within about two weeks of being in a dengue affected area should seek medical evaluation and mention their travel history. Health provider advisories from 2024 and 2025 highlight that early diagnosis, supportive care and appropriate laboratory testing are important to reduce the risk of severe disease, which can involve bleeding, abdominal pain and breathing difficulty.

Information sheets for the public also indicate that people with certain underlying conditions, including previous dengue infection, may face a higher risk of severe outcomes if infected again. Travelers who are older, who have chronic medical problems or who are visiting friends and relatives for extended periods are encouraged to discuss dengue risk in advance with a travel health specialist.

At the same time, US health authorities have not issued broad recommendations against travel to the Americas based on dengue risk alone. Instead, the global notice is framed as a way to increase awareness, enhance mosquito avoidance and promote timely care rather than to restrict tourism or business trips.

How travelers can track evolving dengue hotspots

Because dengue activity varies seasonally and from one locality to another, public health agencies recommend that travelers consult up to date resources as part of trip planning. The CDC travel notices page now maintains a dedicated entry for global dengue, which is updated as new surveillance data become available and as more countries report higher than expected case counts.

CDC reference material on areas with dengue risk supplements the travel notice with regional maps and detailed country lists, indicating where transmission is frequent and where it is sporadic or uncertain. These tools are intended to help travelers, clinicians and tour operators judge relative risk in specific cities or resort regions rather than assuming uniform conditions across an entire country.

In addition to national level advisories, regional bodies such as the Pan American Health Organization publish periodic situation updates describing case trends, circulating virus serotypes and pressure on local health systems. Media outlets and destination specific public health agencies in countries such as Brazil, Argentina, Colombia and Mexico also provide English language summaries during large outbreaks, which can further refine planning for those heading to particular regions.

For now, the CDC’s global dengue notice underscores that dengue is likely to remain a recurring feature of travel in the Americas. Trip planners and travelers are being encouraged to treat mosquito protection and real time information checks as routine steps, similar in importance to reviewing passport validity or entry requirements before departure.