Development of cloned DNA probes for the identification of snail intermediate hosts within the genus Bulinus

DNA fragments have been isolated from Bulinus cernicus and cloned in Escherichia coli strain JM109 using pUC18 as the vector. Four recombinant plasmids designated pBC123, pBC126, pBC127 and pBC134 were selected for further analysis and were shown by both dot and Southern blot hybridisations to have different specificities to species representing the four species groups of Bulinus. Non-specific hybridisation occurred with pBC126 whereas pBC123 and pBC134 hybridised only to B. cernicus. Partial restriction maps of the inserts revealed sequence differences between pBC123 and pBC134. Intermediate specificity was shown by pBC127 as this probe hybridised only to DNA from snails of the B. forskalii group and B. truncatus of the B. truncatus/tropicus complex. The results demonstrate the potential of DNA probes for the identification and characterisation of intermediate hosts of schistosomes.