WASHINGTON, USA – ECNETNews reports that the Pan American Health Organization (PAHO) has issued an epidemiological alert regarding a heightened risk of dengue outbreaks across the Americas due to the increasing prevalence of the DENV-3 serotype. PAHO emphasizes the urgent need for countries to bolster their surveillance, early diagnosis, and clinical management practices to mitigate potential rises in dengue cases.
Dengue fever, which is transmitted by the Aedes aegypti mosquito, comprises four distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. Immunity gained from a single serotype only protects against that specific strain, making individuals more susceptible to severe disease upon subsequent infections with different serotypes. The emerging presence of a new or previously uncommon serotype can lead to increased transmission rates in populations that lack immunity.
DENV-3 Situation Update
The DENV-3 serotype has been detected in several countries throughout the Americas, including Brazil, Colombia, Costa Rica, Guatemala, Mexico, and Peru. In 2024, Argentina confirmed the presence of this serotype, marking its entry into the country. In Brazil and Colombia, a notable surge in DENV-3 cases has been reported, particularly among children, with detections also noted in other Central American and Caribbean nations. This serotype is associated with severe dengue manifestations, even in initial infections, raising significant public health concerns.
The resurgence of DENV-3 in areas unaccustomed to it increases the risk for populations not previously exposed to this strain.
Current Trends and Recommended Actions
In 2024, over 13 million dengue cases were reported in the Americas, with 22,684 classified as severe and 8,186 resulting in fatal outcomes, reflecting a case fatality rate of 0.063%. Early reports from 2025 show that 23 countries and territories have accounted for 238,659 cases, predominantly in Brazil (87%), with Colombia (5.6%), Nicaragua (2.5%), Peru (2.5%), and Mexico (2.5%). Among these, 263 cases were severe, leading to 23 deaths.
PAHO advises enhancing vector control measures, improving diagnostic capabilities within healthcare infrastructures, and ensuring timely treatment to prevent severe complications. Additionally, public education initiatives to minimize mosquito exposure and eliminate breeding grounds are deemed crucial.
The Importance of Vaccination and Ongoing Monitoring
Regarding vaccination, preliminary findings from the phase 3 study of the TAK-003 dengue vaccine reveal that it may provide limited protection against DENV-3, particularly for children lacking prior infections. This emphasizes the necessity for secure vaccination practices and continuous monitoring of any adverse reactions.
PAHO is actively tracking the spread of DENV-3 alongside other serotypes and continues to support countries in enacting effective control and response strategies to combat potential outbreaks. It is vital for healthcare systems to be prepared for an anticipated surge in cases and to reduce the risks of severe complications from this serious disease.
