Molecular approaches to the identification ofBulinusspecies in south-west Nigeria and observations on natural snail infections with schistosomes

Abstract

AbstractThe current study considers the distribution of a small sample of 138Bulinussnails, across 28 localities within eight Nigerian states. Snails were identified using a combination of molecular methods involving both DNA sequencing of a partial cytochrome oxidase subunit 1 (cox1) fragment and restriction profiles obtained from ribosomal internal transcribed spacer (its) amplicons. The results showed that the majority ofBulinussamples tested belonged to the speciesBulinus truncatuswhile only two wereBulinus globosus. The use ofRsaI restriction endonuclease to cleave the ribosomalitsofBulinus, as a method of species identification, was adopted for the majority of samples, this being a quicker and cheaper method better suited to small laboratory environments. Polymerase chain reaction (PCR) amplification of the schistosomeDra1repeat within each of the collectedBulinussamples was employed to determine the extent and distribution of infected snails within the sample areas. Successful amplification of theDra1repeat demonstrated that 29.7% of snails were infected with schistosomes. Sequencing of the partial schistosomeitsfrom a small subset of snail samples suggested that some snails were either penetrated by bothSchistosoma haematobiumandSchistosoma bovismiracidia or hybrid miracidia formed from the two species.