Genetic Diversity and Infection Prevalence of Biomphalaria pfeifferi (Krauss, 1848), the Intermediate Snail Host of Schistosoma mansoni in Gezira State, Sudan

<i>Biomphalaria pfeifferi</i> snails serve as the major intermediate host for intestinal schistosomiasis in Sudan. The genetic structure and infection status of 163 <i>B. pfeifferi</i> collected from six localities in Gezira State, Sudan (East Gezira, Greater Wadmedani, Hasahisa, North Umelgura, South Gezira, and Managil) were characterized. Cytochrome oxidase subunit I (<i>COI</i>) and <i>16S</i> ribosomal RNA (<i>16S rRNA</i>) mitochondrial genes were used for <i>B. pfeifferi</i> molecular identification and genetic diversity investigation. <i>Schistosoma mansoni</i> infection was detected using the traditional cercarial shedding and molecular methods (Sm^F/R primers). Five <i>COI</i> haplotypes and ten <i>16S</i> haplotypes were identified, with haplotype diversity of 0.50 for <i>COI</i> and 0.11 for <i>16S</i>. High evolutionary divergence was observed between groups (Fst = 0.94) for the <i>COI</i>, and low genetic divergence (Fst = 0.04) for the <i>16S</i>, indicating genetic divergence among Sudanese <i>B. pfeifferi</i>, with the <i>16S</i> showing lower divergence than the <i>COI</i>, consistent with a post-bottleneck population expansion. Cercarial shedding detected an overall infection prevalence of 3.6% (8/219), with only two snails from Hasahisa shedding <i>S. mansoni</i> cercariae. The Sm^F/R primers revealed a higher infection prevalence of 7.4% (12/163), with all <i>S. mansoni</i> positive samples found at the Hasahisa site. Findings highlight the value of molecular diagnostic tools for accurate surveillance and emphasize the need for site-specific control strategies.