Characterisation ofLymnaea cubensis,L. viatrixandL. neotropican. sp., the main vectors ofFasciola hepaticain Latin America, by analysis of their ribosomal and mitochondrial DNA

Abstract

Although, in the endemic areas throughout the world, human fascioliasis presents varying patterns in its epidemiology, the species of lymnaeid snail that act as intermediate hosts and vectors are always crucial in the transmission of the causative parasites. Species in the Galba/Fossaria group of snails, such as Lymnaea cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and Galba truncatula, appear to be frequently involved in the transmission of Fasciola hepatica in Central and South America, although specific classification within this morphologically and anatomically confusing group is often very difficult. To explore the potential use of molecular analyses in the identification of vector snails, regions of the ribosomal DNA - the small subunit (18S) gene and internal transcribed spacers (ITS-2 and ITS-1) - and of the mitochondrial DNA - the cytochrome c oxidase subunit I (COI) - of wild-caught lymnaeid snails of L. cubensis, L. viatrix var. A ventricosa, L. viatrix var. B elongata and G. truncatula have been sequenced. The samples of the Latin American species included specimens from the respective type localities. The genetic distances observed and the results of phylogenetic analyses demonstrate that two different species exist within L. viatrix. Lymnaea neotropica n. sp. (=L. viatrix var. B elongata) is here proposed for specimens from Lima, Peru, and is differentiated from L. viatrix (=L. viatrix var. A ventricosa), L. cubensis and G. truncatula. The data collected on the 18S ribosomal-RNA gene indicate that the snails investigated may cover more than one supraspecific taxon. The ITS-2, ITS-1 and COI nucleotide sequences are clearly useful markers for the differentiation of these morpho-anatomically similar lymnaeid species. The numerous microsatellite repeats found within ITS-2 are potential tools for differentiation at population level.

CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh

“…Fasciola hepatica is mainly transmitted by small size lymnaeid species of the Galba/Fossaria group (Bargues et al 2007(Bargues et al , 2011a, including Galba truncatula as the main vector and the only one in Europe, but also present in Asia, Africa and South America. Fasciola gigantica is transmitted by lymnaeids of larger size of the Radix group (Bargues and Mas-Coma, 2005).…”

Distribution of Lymnaeidae (Mollusca: Pulmonata), intermediate snail hosts of Fasciola hepatica in Venezuela

“…In contrast, this study was able to clearly distinguish between the two taxa using characters of the male reproductive system. The validity of these anatomical markers has been confirmed by a genetic variability analysis based on 12 enzyme loci (Durand et al 2002) and by the analysis of several DNA sequences such as the small subunit (18S) gene, internal transcribed spacers (1 and 2) and the cytochrome c oxidase subunit I (Bargues et al 2007). …”

Assessment of molluscicidal activity of essential oils from five Azorean plants against Radix peregra (Müller, 1774)

“…Even though, the intermediate host belongs, normally, to the Lymnaeidae family, Fasciola hepatica reveals a high ability to parasite a large host diversity, e.g. Lymnaea humilis, Lymnaea bulimoides, Lymnaea cubensis, Lymnaea viatrix and Lymnaea neotropica, Lymnaea columella (in Latin America), and Lymnaea bulimoides (in North America) (Cruz-Mendoza et al, 2004;Bargues et al, 2007;Lima et al, 2009). In Europe (including Azores) the common liver fluke, F. hepatica, its a parasite whose primary intermediate host is the freshwater snail Galba (=Lymnaea) truncatula Müller, 1774.…”