Descriptions of digenean parasites from three snail species, Bithynia fuchsiana (Morelet), Parafossarulus striatulus Benson and Melanoides tuberculata Müller, in North Vietnam

For first time, 3 species of prosobranchial snails (Bithynia fuchsiana, Parafossarulus striatulus (Bithyniidae) and Melanoides tuberculata (Thiaridae)) from North Vietnam were studied for presence of the parthenitae and cercariae of Trematoda. The morphology of 12 species of larvae belonging to 8 families (Cyathocotylidae, Pleurogenidae, Lecithodendriidae, Paramphistomidae, Heterophyidae, Notocotylidae, Psilostomidae and Echinostomatidae) was described. Data on the life cycles of 3 species (Echinochasmus japonicus, Notocotylus intestinalis and Sphaeridiotrema monorchis) as well as molecular data on 28S rDNA were obtained. There was no intraspecific variability found in any of the sequences examined. The 28S rDNA sequence length determined for N. intestinalis was 1315 bp, while that of S. monorchis was 1292 bp, and that of E. japonicus was 1288 bp.