Spatial distribution and habitat suitability of tsetse ( Glossina spp .) in Côte d’Ivoire: An ensemble modeling approach to support targeted disease control

Résumé fourni par la source

Abstract Background Tsetse are vectors of trypanosomes responsible for African animal trypanosomosis (AAT) and human African trypanosomiasis (HAT). While Côte d’Ivoire has successfully eliminated HAT as a public health problem and approaches elimination of transmission, AAT remains a major obstacle to agriculture and livestock production. Understanding the spatial distribution of tsetse is essential for prioritizing and sustaining disease control and elimination efforts. Methodology/Principal Findings Using 1,702 occurrence records from the national tsetse atlas we modeled the habitat suitability of the nine tsetse species present in Côte d’Ivoire. We identified suitable habitats in unsampled areas and quantified environmental constraints on tsetse distribution. Resampling the data to a 1km x 1km grid produced spatially explicit outputs at a resolution more relevant for operational planning. An ensemble modeling approach was employed integrating four algorithms—Random Forest, XGBoost, Maximum Entropy (MaxEnt), and Generalized Additive Models (GAM)— with satellite-derived environmental and anthropogenic predictors—which achieved high predictive accuracy, area under the curve and True Skill Statistics 0.80 and 0.83, respectively. Distance to waterbodies, soil moisture, distance to protected areas, maximum land surface temperature, and sheep density were key drivers of habitat suitability. Importantly, the models identified suitable habitats in 11 administrative regions not covered by the atlas, providing an improved national tsetse risk profile. Conclusions/Significance These results provide a detailed assessment of the ecological suitability of tsetse across Côte d’Ivoire and their persistence in agroecological mosaics with high human and livestock densities. We offer a high-resolution blueprint for vector and disease control, particularly in areas where field data are currently lacking. We provide a robust framework for evidence-based decision-making within the Progressive Control Pathway (PCP) for AAT by enabling the identification of priority areas and resource allocation optimization to improve livestock productivity through more effective AAT control and reduce the risk of resurgence of HAT. Author Summary Tsetse flies are a major threat to health across sub-Saharan Africa, transmitting parasites that cause sleeping sickness in humans and nagana in livestock. While Côte d’Ivoire has significantly reduced human cases, the impact on livestock still hinders economic growth. To protect both people and animals, health authorities need accurate maps showing where different tsetse species live. We analyzed over 1,700 records of tsetse from across Côte d’Ivoire, combining them with satellite-based data on temperature, vegetation, and water. Using machine-learning models, we created detailed maps predicting habitat suitability for nine tsetse species. Our findings reveal that different species confine to specific environments, with some living near rivers and others moving into areas with high human and livestock activity. These maps offer a high-resolution layer to inform HAT and AAT disease surveillance and control. By knowing where flies thrive, resources can be precisely allocated to high-risk areas. This study can help protect livestock, boost animal productivity, and ensures that human sleeping sickness does not return to regions where it was previously eliminated.

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