Characteristics of Anopheles gambiae s.l larval breeding sites and spatiotemporal analysis of malaria transmission risk in Djilakh, a hotspot village in central Senegal

Background: The progress made in the fight against malaria has resulted in a reduction of the burden in Senegal on a national scale. Transmission levels tend to be low overall, but there is considerable spatial heterogeneity, which necessitates the identification of the factors responsible for regional or local disparities in order to accelerate the elimination process. The objective of this study is to demonstrate the impact of the functionality of larval breeding sites on the evolution of malaria risk in Djilakh, a hotspot village beloging to Mbour health district in central Senegal. Methods This study cover the period from 2013 to 2017. Cartographic and biological data collection occurred during the rainy season (June-November), with three outings per year. Only malaria cases confirmed by RDT (rapid diagnostic test) were considered. Rainfall data were gathered at the synoptic station of the Mbour department. To assess the impact of larval breeding sites on malaria transmission, logistic regression and Poisson models were employed. Some data were analysed using Excel, with cumulative means and frequencies calculated. The QGIS Desktop 2.2.0 mapping software was used to create the maps. Results The results of this study demonstrate that the deposits explored in this village correspond to natural temporary ponds, characterised by clayey and clayey-sandy soils. A review of data on meteorology and malaria morbidity indicates that malaria transmission is influenced by precipitation. The correlation between malaria morbidity and breeding site positivity varied throughout the rainy season, depending on the size and stability of breeding sites. Additionally, the results indicate that the type of land use and its spatial distribution play an important role in estimating the risk of malaria transmission in the village. The incidence of malaria cases is significantly higher in hamlets situated in close proximity to larval breeding sites, exhibiting a gradual decline with increasing distance from these hamlets. Conclusions The findings of this study represent a preliminary step towards a more comprehensive understanding of the environmental factors influencing the persistence of residual malaria transmission in Senegalese hotspot villages, despite the deployment of various vector control measures. The results of this study indicate a need for targeted control actions in identified risk areas in order to better control the malaria endemic.