Epidemiological Update: Dengue and Chikungunya in the Americas Region - 20 October 2026

Given the increase in dengue cases observed in some countries of the Andean, Central American, and Caribbean subregions of the Americas Region, as well as the increase in chikungunya cases experienced between late 2025 and 2026, accompanied by the resurgence of chikungunya transmission in countries and territories of the Region where no viral circulation had been recorded for several years, the anticipated intensification of the El Niño phenomenon over the coming months, and the approaching peak season for dengue and chikungunya transmission in South America, the Pan American Health Organization/World Health Organization (PAHO/WHO) urges Member States to maintain and strengthen epidemiological, virological, and entomological surveillance, as well as to strengthen diagnostic capacity, to ensure early detection and timely clinical management of cases, and to consolidate integrated vector management efforts, with the  aim of limiting transmission and reducing morbidity and mortality associated with dengue, chikungunya,  and other arboviral diseases.