The Americas at risk of dengue outbreaks

The Pan American Health Organization/World Health Organization (PAHO/WHO) has issued a call to its Member States, urging them to take measures to prepare for a potential escalation in cases of dengue and other arboviruses within the Region. This call follows an observed increase in the circulation of DENV-3 across the Southern Hemisphere of the Americas. Between Epidemiological Week (EW) 1 and EW 4 of 2025, a total of 23 countries and territories in the Americas region reported 238,659 cases of dengue. The six countries that accounted for 98% of cases in the region were: Brazil with 194,564 cases (87%), Colombia with 12,740 cases (5.6%), Nicaragua with 5,702 cases (2.5%), Peru with 5,735 cases (2.5%), and Mexico with 5,649 cases (2.5%). Of the total reported cases, 57,899 (24%) were laboratory-confirmed, of which 263 were characterised as severe dengue (0.11%), and 23 fatal cases were recorded (CFR 0.010%). Four serotypes of dengue virus are circulating in the Americas region until EW 4 of 2025. In particular, Brazil, Costa Rica, El Salvador, Mexico, and Panama reported the simultaneous circulation of DENV-1, DENV-2, DENV-3, and DENV-4.