Genetic Diversity of Schistosoma haematobium Populations in Northwest Nigeria Using Microsatellite Markers

Understanding the genetic diversity and population structure of Schistosoma haematobium is essential for tracking transmission dynamics, predicting reinfection patterns, and evaluating the impact of mass drug administration programmes. This study characterised the genetic diversity of S. haematobium populations in four endemic local government areas of Sokoto State, Northwest Nigeria, using microsatellite markers. Adult worms were recovered from experimentally infected Biomphalaria and Bulinus intermediate host snails obtained from endemic transmission sites. A total of 320 individual worms were genotyped at eight polymorphic microsatellite loci using capillary electrophoresis. Population genetic analyses were performed using FSTAT, STRUCTURE, and Arlequin software. High levels of allelic diversity (mean He = 0.74) and significant genetic differentiation between populations from different transmission sites (FST = 0.18) were documented. Bayesian clustering identified three genetically distinct population clusters corresponding broadly to irrigation canal, river, and reservoir transmission environments. Signatures of recent population bottleneck were detected in communities that had received three or more praziquantel treatment rounds. These results have direct implications for understanding reinfection sources and optimising mass drug administration targeting in Northwest Nigeria. Keywords: Schistosoma haematobium, genetic diversity, microsatellite markers, population structure, Northwest Nigeria.