Spatiotemporal Analysis of Dengue Incidence and Associated Factors: An Ecological Study Across Municipalities in Bahia, Brazil (2019-2024)
Year: 2026
Type: article
Study design: Observational Study
Abstract: INTRODUCTION: Dengue remains a major public health challenge in Brazil, characterized by substantial spatial and temporal heterogeneity in transmission. This study aimed to analyze the spatiotemporal characteristics of dengue incidence across the municipalities of Bahia, Brazil, throughout the study period and to identify socioeconomic, demographic, and urban infrastructure factors associated with dengue incidence in the years with the lowest and highest state-level incidence. METHODS: An ecological study was conducted using probable dengue cases reported in Bahia from 2019 to 2024. The complete six-year series was analyzed descriptively to characterize temporal variation and the spatial distribution of dengue incidence across 417 municipalities. Incidence rates per 100,000 inhabitants were smoothed using a local empirical Bayes estimator. Spatial autocorrelation was assessed annually using Global Moran's I and Local Indicators of Spatial Association (LISA). Ordinary least squares (OLS), spatial autoregressive (SAR), and spatial error models (SEMs) were fitted for 2021 and 2024, the years with the lowest and highest state-level incidence, respectively, to contrast low- and high-transmission contexts. Socioeconomic, demographic, and urban infrastructure indicators from the 2010 Census and 2020 MUNIC (Municipal Basic Information Survey) were treated as time-invariant in both regression models. RESULTS: Between 2019 and 2024, 506,792 probable dengue cases were reported across the municipalities of Bahia. The incidence was lowest in 2021 (166.6 cases per 100,000 inhabitants) and highest in 2024 (1,558.7 cases per 100,000 inhabitants). Significant positive spatial autocorrelation was observed in all years, with high-high clusters shifting from the Far West region in 2021 to the South-Central region in 2024. SAR showed the best fit. Per capita household income was positively associated with incidence in 2021 (β=0.003; 95% CI: 0.001-0.005) and 2024 (β=0.002; 95% CI: 0.000-0.003). In 2024, sewerage coverage (β=-0.006; 95% CI: -0.011 to -0.001) and the proportion of the population classified as Black or mixed-race (β=-0.020; 95% CI: -0.032 to -0.008) were negatively associated with incidence. CONCLUSIONS: The findings demonstrate marked spatiotemporal heterogeneity and spatial clustering of dengue incidence in Bahia and highlight the relevance of socioeconomic, demographic, and urban infrastructure conditions to its spatial distribution. The findings provide geospatial evidence to support geographically targeted dengue surveillance and control strategies.
Source: Cureus
Institution: Universidade Federal da Bahia
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7214331986