Two Decades of Dengue in Bangladesh (2001-2024): Epidemiologic Trends, Geographic Spread and Climatic Drivers

Bangladesh has experienced a marked escalation in dengue since 2001, culminating in 321,179 reported cases and 1705 deaths in 2023. The objective of this narrative review is to analyse 24 years of surveillance data to describe temporal trends, the transition from urban-centric to nationwide endemicity and the influence of climatic drivers. This review synthesises national surveillance and published reports from 2001 to 2024 to assess demographic risk, geographic spread and environmental factors. Young adults (21-30 years) consistently account for the largest share of infections (28.82% in 2024). In contrast, adults over 50 years suffer disproportionate mortality (15.65% of deaths in 2024) despite a smaller share of infections (7.15%). Since 2019, transmission has extended beyond urban centres such as Dhaka into peri-urban and other districts. This geographical diffusion is driven by the rapid urbanisation of other peripheries, infrastructure development that creates new vector habitats and accelerated population mobility which connects hyper-endemic urban hubs with susceptible rural communities. We identify priority actions such as targeted risk communication for young adults, improved access to healthcare for older adults and climate-adaptive vector control strategies integrated with urban services and strengthened surveillance. It is essential to address these factors to reduce the dengue burden and improve health outcomes in Bangladesh to control mosquito populations. Lessons are transferable to other dengue-affected countries when adapted to local demographic and environmental contexts and embedded in regional collaboration and climate-responsive policy.