Genetic Diversity and Ecological Distribution of Bulinus Populations in Southern Benin Using PCR-RFLP Analysis

Schistosomiasis remains a major public health concern in Benin. Freshwater snails of the genus Bulinus serve as intermediate hosts for schistosomes, trematode parasites responsible for bilharzia. The urinary form, caused by Schistosoma haematobium, is the most prevalent and is primarily transmitted by Bulinus truncatus and Bulinus globosus, whereas the intestinal form, caused by Schistosoma mansoni, is transmitted by Bulinus forskalii. Effective control strategies require an understanding of the molecular diversity and genetic structure of Bulinus populations. Bulinus samples were collected from six localities in southern Benin: Sô-Ava, Azowlissè, Aplahoué, Kpinnou, Houéyogbé, and Za-Kpota. Samples were preserved in absolute alcohol. DNA was extracted, and fragments of the Cox1 and SSU genes were amplified. Molecular diversity was assessed using PCR-RFLP, with amplified products digested using HaeIII, HinfI, and DdeI restriction enzymes. Molecular variance analysis (AMOVA) was performed to evaluate population structure. AMOVA revealed heterozygosity deficits in Bulinus populations from all six localities and deviations from panmixia in Sô-Ava, Aplahoué, Houéyogbé, Kpinnou, and Za-Kpota. Enzymatic digestion indicated monomorphism for B. globosus in Za-Kpota and Houéyogbé with the SSU gene and for B. truncatus in Sô-Ava and Azowlissè with the Cox1 gene. Conversely, molecular polymorphism was observed for B. globosus in Sô-Ava and Aplahoué with the Cox1 gene, whereas B. truncatus in Sô-Ava and Azowlissè showed identical SSU gene profiles. These findings provide preliminary insights into the molecular diversity and genetic structure of Bulinus populations in southern Benin. The observed genetic variability and structure have implications for understanding the transmission dynamics of S. haematobium and for designing targeted schistosomiasis control strategies.