Ambient PM2.5 exposure and increased dengue case fatality: a global multi-country analysis

Dengue is a rapidly expanding, climate- and environment-sensitive vector-borne disease. However, the role of air pollution in shaping its severity remains poorly understood. We aimed to assess whether long-term exposure to ambient fine particulate matter (PM 2 . 5 ) contributes to increased dengue case fatality rates (CFRs) across endemic countries. We conducted a multi-country ecological study across 20 dengue-endemic nations in Asia, Africa, and Latin America during the period 2020–2024. National dengue surveillance data were integrated with satellite-derived PM 2 . 5 estimates and socioeconomic–climatic covariates. Associations between long-term PM 2 . 5 exposure and dengue CFRs were examined using generalized linear mixed-effects models. Results revealed that the mean dengue CFR across study countries was 0.20% (range 0.05–0.77), with an annual mean PM 2 . 5 exposure of 27.3 μg/m 3 (range 7.4–77.5 μg/m 3 ). However, countries exceeding 35 μg/m 3 PM 2 . 5 (e.g., Bangladesh, Burkina Faso, Indonesia) recorded 3–5 times higher CFRs than countries below 15 μg/m 3 (e.g., Brazil, Ecuador, Costa Rica) (p35 μg/m 3 had 3–5× higher dengue fatality rates • Dry-season PM 2 . 5 in Bangladesh nearly doubled dengue fatality risk • Higher GDP per capita was associated with lower dengue case fatality rates • Findings reveal environmental injustice in dengue outcomes across regions