Dengue virus particles. Source: NIAID via Wikimedia Commons.
Highlights
- More than 122,000 dengue cases were reported across the Americas during the first weeks of 2026.
- Brazil, Colombia, Peru, Mexico, and Panama continue to report active transmission.
- Spread of multiple dengue virus serotypes could increase future outbreaks.
After a historic dengue epidemic swept across Latin America in 2024, public health officials hoped the worst was behind them. While case numbers declined substantially during 2025, dengue remains firmly entrenched across the Americas. Early surveillance data suggest the virus will continue to challenge health systems throughout 2026.
In February 2026, the Pan American Health Organization (PAHO) released a new epidemiological update summarizing dengue activity across the region. The report provides a snapshot of where transmission is occurring, which countries are experiencing increases, and why public health authorities remain concerned despite lower case counts compared to recent epidemic years.
Dengue Cases Have Fallen Since the Historic 2024 Epidemic
The good news is that dengue activity in 2025 was considerably lower (i.e., 66% decrease) than the record-breaking outbreak observed in 2024.
According to PAHO, approximately 4.5 million dengue cases were reported across the Americas in 2025, compared with more than 13 million cases reported during the unprecedented 2024 epidemic. Severe dengue cases and deaths also declined from the previous year.
However, lower does not mean low.
By epidemiological week 4 of 2026, countries in the Americas had already reported more than 122,000 dengue cases, including over 22,000 laboratory-confirmed infections and hundreds of severe dengue cases. Public health agencies remain on alert as transmission intensifies during seasonal mosquito activity.
Brazil Continues to Carry the Largest Burden
As in previous years, Brazil remains the epicenter of dengue activity in the Americas.
During 2025, Brazil reported more than 1.6 million probable dengue cases and nearly 1,800 deaths. By early 2026, more than 62,000 suspected cases had already been reported, accounting for a substantial proportion of the region’s total dengue burden.
The country’s size, climate conditions, and widespread distribution of Aedes aegypti mosquitoes make dengue control particularly challenging. Health authorities have also observed increased circulation of DENV-3, a serotype that has been linked to outbreaks in populations with limited prior immunity.
Multiple Countries Are Experiencing Seasonal Increases
Beyond Brazil, active dengue transmission continues across much of Latin America.
Colombia reported more than 125,000 dengue cases in 2025 and had already documented more than 9,000 cases by early 2026. Peru, Panama, Mexico, Ecuador, and Bolivia have also reported ongoing transmission and seasonal increases in case numbers.
Several countries are observing the expected rise in dengue activity that accompanies warmer temperatures and increased mosquito abundance. While these trends are not yet comparable to the explosive outbreaks of 2024, they highlight how quickly dengue can rebound when environmental conditions become favorable.
Why Public Health Officials Remain Concerned
One of the most important findings from the PAHO report is the continued circulation of multiple dengue virus serotypes throughout the region.
Brazil, Colombia, Mexico, Panama, Costa Rica, El Salvador, and Puerto Rico all reported simultaneous circulation of DENV-1, DENV-2, DENV-3, and DENV-4 during 2025.
This matters because infection with one serotype does not provide long-term protection against the others. In fact, secondary infections with a different serotype are associated with a higher risk of severe dengue due to a phenomenon known as antibody-dependent enhancement.
As populations are exposed to multiple circulating serotypes, the potential for future outbreaks and severe disease increases.
The Importance of Surveillance and Vector Control
PAHO is urging countries to strengthen surveillance systems, maintain clinical preparedness, and expand mosquito control efforts. The organization also emphasizes the need for rapid identification of transmission hotspots and community-based interventions to eliminate mosquito breeding sites.
The primary vector, Aedes aegypti, thrives in urban environments where standing water accumulates in containers, discarded tires, and household water storage systems. Reducing mosquito populations remains one of the most effective tools for preventing outbreaks.
Public health authorities are also encouraging healthcare workers to remain vigilant for warning signs of severe dengue, which can progress rapidly without appropriate medical management.
Looking Ahead
Although the Americas are no longer experiencing the unprecedented dengue emergency seen in 2024, the virus remains a major public health threat throughout Latin America.
Early 2026 data show that dengue transmission continues across the region, with active outbreaks, multiple circulating serotypes, and favorable environmental conditions for mosquito expansion. These factors underscore the need for continued surveillance, vector control, and public awareness.
The lesson from recent years is clear: dengue can rebound quickly. Sustained public health investment and community engagement will be essential to preventing the next major epidemic.
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