Molecular Characterisation of Schistosoma haematobium Infecting School Children in Nasarawa State, North Central Nigeria, Using Internal Transcribed Spacer Sequencing

Molecular characterisation of Schistosoma haematobium populations using internal transcribed spacer sequencing provides insights into genetic diversity, hybridisation events, and population structure that inform control strategies and vaccine development. This study molecularly characterised S. haematobium infecting school children in riparian communities of Nasarawa State, North Central Nigeria. Miracidia hatched from pooled urine samples of 120 infected children from four communities were individually preserved in 80% ethanol. DNA was extracted from single miracidia and amplified by PCR using ITS1 and ITS2 primers. Amplicons were sequenced on the Sanger platform and analysed using MEGA11 software. Population genetic analysis employed DnaSP and Arlequin software. A total of 180 individual miracidia sequences were obtained. ITS1 haplotype network revealed 12 distinct haplotypes, with one dominant haplotype present across all communities. Evidence of hybridisation with S. bovis was detected in 6.7% of miracidia based on intermediate ITS2 sequence positions. Significant genetic differentiation was observed between communities separated by greater than 15 km. Nucleotide diversity was moderate, suggesting a relatively stable but geographically differentiated parasite population. The detection of bovine-human hybrid schistosomes raises concern for altered host specificity and drug response. The study contributes important molecular epidemiological data on S. haematobium in North Central Nigeria and recommends integration of molecular surveillance into national schistosomiasis control programmes alongside drug administration. Keywords: Schistosoma haematobium, ITS sequencing, hybridisation, population genetics, Nasarawa State