Molecular approaches for identification of Bulinus species from White and Blue Nile, Sudan

Abstract

Background: The systematic of Bulinus species freshwater snails plays a crucial role in understanding the transmission of urinary schistosomiasis, in monitoring the present and future infection levels among the human population and in the distribution of the disease in the endemic areas. This study aimed to identify the Bulinus species from three states in the Sudan: Khartoum, Gezira and White Nile States. Methods and materials: A total of 1203 Bulinus snail were collected from the three States. The morphological Results showed that 32% were B. forskalii and 78% were B. Truncatus. However, the morphological methods had their limitations. A 700 bp fragment of the mitochondrial gene cytochrome oxidase subunit 1 (cox1) was further amplified and sequenced to determine the subtypes within the two species characterized phenotypically. Results: Haplotype and phylogeny analyses of the sequenced cox1 gene characterized two haplotypes in B. forskalii and four in B. truncatus. Although the use of sequencing for species identification is very expensive and time-consuming, the diversity within cox1 gene is a useful supporting tool for identifying Bulinus snails in schistosomiasis low and high risk areas. The genetic structure of the intermediate host snails and their susceptibility to the infection by the parasite are important factors in the transmission of the disease. Conclusion: The importance of the technique, reported here, in relation to planning a proper schistosomiasis control programme in the Sudan was discussed, and is recommended to be determined before setting a snail control strategy.