Spatio-temporal heterogeneity of urban malaria in Libreville, Gabon (2012-2023): Neighborhood-level hotspot analysis for micro-stratified control

Background In Libreville, Gabon, the Melen sentinel site has monitored malaria among febrile children for over a decade, offering a lens on intra-urban transmission. We aimed to characterize neighborhood-level spatial and temporal dynamics (2012–2023) and identify high-risk areas for micro-stratified control. Methods Geographic and parasitological data from 9,507 children (Jan 2012–Dec 2023) were analyzed. Diagnosis used standard microscopy (thick/thin smears). Plasmodium falciparum prevalence (PfPR) was calculated for 44 neighborhoods across four periods. Neighborhoods were classified by adapted WHO endemicity thresholds and grouped into socio-spatial categories (urban, semi-urban, shanty-town, semi-rural). Global spatial autocorrelation was tested with Moran’s I, then local Getis–Ord Gi* identified hotspots and coldspots. Results By category, semi-rural and semi-urban areas consistently showed higher prevalence than urban and shanty-town areas; in 2023, PfPR peaked at 50.9% (semi-rural), 46.5% (semi-urban), 44.6% (shanty-town), and 38.0% (urban). WHO classification showed a shift from mostly mesoendemic neighborhoods in 2015 to 41.5% hyperendemic in 2023. Persistently high-burden neighborhoods included Nkoltang (semi-rural), Essassa (semi-rural), and Pk5 (shanty-town). Hotspots were detected in Montalier (urban, 2012–2013), Essassa (semi-rural) and Nzeng Ayong (urban, 2015–2016), and Bangos (shanty-town, 2018–2019); Bambouchine (semi-rural, 2015–2016), Pk8 (2018–2019), and Okolassi (2023) were coldspots. Conclusions Urban malaria in Libreville is highly heterogeneous and dynamic, with predominant mesoendemic neighborhoods and recurrent hotspots. Findings support micro-stratified strategies prioritizing recurrent clusters and integrating fine-scale spatial analytics into national surveillance.