Battling dengue in a warming world: How climate and urbanization shape transmission in low- and middle-income countries (a rapid review)

Background: Dengue fever is a globally prevalent vector-borne disease, with low- and middle-income countries (LMICs) experiencing a disproportionate burden. Transmission patterns are increasingly influenced by rising global temperatures and rapid urbanization, yet no recent review has synthesized how these environmental factors are reshaping dengue dynamics in LMICs. Methods: We conducted a rapid systematic review following a registered protocol (PROSPERO: CRD42025635982). Six databases (MEDLINE, Embase, Global Health, SciELO, Global Index Medicus and Web of Science) were searched for peer-reviewed studies published between January 2020 and November 2024. Studies were screened for climate or urbanization factors affecting dengue transmission in LMICs. Study quality was assessed using the Mixed Methods Appraisal Tool for empirical studies and a structured assessment for modeling studies. Findings were synthesized narratively. Results: Of the 65 included studies, 65% reported a positive association between rising temperatures and increased dengue transmission, often attributed to intensified mosquito activity and longer transmission seasons. Urbanization was assessed in 35% of studies, with unplanned growth, informal settlements, and inadequate infrastructure frequently associated with increased risk. Several studies reported geographic expansion into highland and peri-urban areas, as well as seasonal shifts, including earlier onset and prolonged transmission periods. Urban heat islands and land-use change were commonly associated with localized transmission hotspots. Government responses were documented in 29% of studies, though many were hindered by fragmented surveillance systems, limited cross-sector coordination, or insufficient integration of climate data into public health planning. Conclusion: Climate change and urbanization are reshaping the spatial and temporal dynamics of dengue in LMICs. Adaptive responses require strengthened surveillance and climate-informed planning in resilient urban infrastructure to reduce future transmission risks. Author summary: Dengue fever is spreading in many low- and middle-income countries, and this review helps explain how climate and urbanization are contributing to that change. We reviewed recent studies published between 2020 and 2024 to understand how rising temperatures, rainfall patterns, humidity, and urban development are affecting where and when dengue occurs. We found that warmer temperatures were often linked with increased dengue transmission, partly because mosquitoes can become more active and the virus can spread more efficiently under certain temperature conditions. We also found that unplanned urban growth, crowded housing, poor drainage, and limited access to clean water can create more places for mosquitoes to breed. Several studies showed that dengue is appearing in new areas, including higher-altitude and peri-urban regions, and that transmission seasons may be starting earlier or lasting longer. Our review also identified early implementation of government-led early warning systems and risk mapping tools; however, many response efforts remain constrained by fragmented systems, limited intersectoral coordination, and insufficient resources. These findings show the need for climate-informed public health planning and resilient urban infrastructure to reduce future dengue transmission risk.