Dengue virus at the landscape scale in Cambodia: Linking climate and land use dynamics with Dengue ecology in Southeast Asia

Dengue remains a major public health challenge in Cambodia, where transmission dynamics are driven by interactions among human infections, Aedes vector populations, land use and climatic variability. Hence, longitudinal evidence linking laboratory-confirmed dengue infections with entomological and environmental indicators remains limited. This study aimed to investigate the dengue incidence and Aedes vector populations in relation to climate and land use dynamics. Adult Aedes mosquitoes have been collected across six major land-use types using BG-Sentinel traps every 2 months during 4 years. In parallel, a prospective household-based cohort study was conducted to enrolling individuals residing in trap-associated households. Blood samples have been collected twice annually and tested for anti-dengue virus (DENV) IgM and IgG antibodies using in-house ELISA assays. Entomological, serological, and climatic data were integrated and analyzed using different models to assess immediate and delayed associations between vector density, climate variables and dengue cases. Aedes aegypti was consistently more abundant across all habitats, particularly in urban and wetland landscapes. Aedes albopictus predominated in wooded and residential areas, reflecting a preference for shaded habitats, though low dry-season abundance limited broader ecological inference. Among approximately 70 individuals with paired samples, ~ 17% were dengue-positive, corresponding to an estimated incidence of 8.6 infections per 100 person-years. Aedes aegypti abundance was significantly associated with dengue incidence, whereas Ae. albopictus showed no significant relationship. Distributed lag analyses further identified delayed effects of Ae. aegypti density on dengue risk within 0–4 weeks. This integrated study highlights the combined influence of human infection patterns, vector ecology, climatic variability, and landscape context on dengue transmission in central Cambodia, supporting to improve dengue risk assessment and location-specific vector control interventions.