Search results for "lymnaeidae"
showing 10 items of 16 documents
Hemocyanin genes as indicators of habitat shifts in Panpulmonata?
2018
Hemocyanin is the primary respiratory protein for the majority of the Mollusca and therefore directly interfaces with the physiological requirements of each species and the environments to which they are adapted. Hemocyanin is therefore likely to have been evolutionarily imprinted by significant habitat shifts. In the gastropod clade Panpulmonata (>30,000 species) major realm transitions have occurred multiple times independently and may have contributed to the diversification of this group. Yet, little is known about the adaptive changes linked to these habitat shifts. In order to gain deeper insight into the evolution of panpulmonate hemocyanins and to infer possible impacts associated wi…
Phylogenetic analysis of Lymnaeid snails based on 18S rDNA sequences.
1997
The 18S rDNA sequences of the six most common European Lymnaeidae species (Mollusca:Gastropoda:Basommatophora) have been obtained by direct PCR cycle sequencing and silver staining methods. The sequence alignment and secondary structures of the 18S rRNA gene of Lymnaea stagnalis, L. auricularia, L. peregra, L. palustris, L. glabra, and L. truncatula are analyzed. This gene proves to be a good marker for both specific determination and supraspecific lymnaeid phylogeny. The malacological importance is evident, considering the specific determination problems of individual snails and the present systematic chaos in Lymnaeidae due to their pronounced morphoanatomic uniformity, which makes a clas…
SSU rDNA Characterization of Lymnaeid Snails Transmitting Human Fascioliasis in South and Central America
1997
The small subunit (18S) rRNA gene sequences of the lymnaeid morphs I and II (Mollusca: Gastropoda: Basommatophora: Lymnaeidae) transmitting human fascioliasis in the high endemic zone of the northern Bolivian Altiplano and of Lymnaea cubensis from Mexico and Guadeloupe island (Caribbean) have been obtained by direct polymerase chain reaction PCR cycle sequencing and silver staining methods and compared to that of the 6 most common European Lymnaeidae species. Results allow us to establish definitively the distinction between the lymnaeids from the northern Bolivian Altiplano and L. cubensis. Lymnaea cubensis is a valid species distributed in North and Central America but absent in the north…
DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with d…
2011
Abstract Background Livestock fascioliasis is a problem throughout Ecuador, Colombia and Venezuela, mainly in Andean areas where the disease also appears to affect humans. Transmission patterns and epidemiological scenarios of liver fluke infection have shown to differ according to the lymnaeid vector snail species involved. These Andean countries present the vectors Lymnaea cousini, L. bogotensis and L. ubaquensis, unknown in the rest of Latin America. An exhaustive combined haplotype study of these species is performed by means of DNA sequencing of the nuclear ribosomal 18S RNA gene, ITS-2 and ITS-1, and mitochondrial DNA cox 1 gene. Results The conserved 5.8S rDNA sequence corroborated t…
Fasciola hepatica and lymnaeid snails occurring at very high altitude in South America.
2002
Fascioliasis due to the digenean species Fasciola hepatica has recently proved to be an important public health problem, with human cases reported in countries of the five continents, including severe symptoms and pathology, with singular epidemiological characteristics, and presenting human endemic areas ranging from hypo- to hyperendemic. One of the singular epidemiological characteristics of human fascioliasis is the link of the hyperendemic areas to very high altitude regions, at least in South America. The Northern Bolivian Altiplano, located at very high altitude (3800–4100 m), presents the highest prevalences and intensities of human fascioliasis known. Sequences of the internal tran…
DNA multigene sequencing of topotypic specimens of the fascioliasis vector Lymnaea diaphana and phylogenetic analysis of the genus Pectinidens (Gastr…
2012
Freshwater lymnaeid snails are crucial in defining transmission and epidemiology of fascioliasis. In South America, human endemic areas are related to high altitudes in Andean regions. The species Lymnaea diaphana has, however, been involved in low altitude areas of Chile, Argentina and Peru where human infection also occurs. Complete nuclear ribosomal DNA 18S, internal transcribed spacer (ITS)-2 and ITS-1 and fragments of mitochondrial DNA 16S and cytochrome c oxidase (cox)1 genes of L. diaphana specimens from its type locality offered 1,848, 495, 520, 424 and 672 bp long sequences. Comparisons with New and Old World Galba/Fossaria, Palaearctic stagnicolines, Nearctic stagnicolines, Old Wo…
European Lymnaeidae (Mollusca: Gastropoda), intermediate hosts of trematodiases, based on nuclear ribosomal DNA ITS-2 sequences.
2001
Freshwater snails of the family Lymnaeidae are of a great parasitological importance because of the very numerous helminth species they transmit, mainly trematodiases of large medical and veterinary impact. The present knowledge on the genetics of lymnaeids and on their parasite-host inter-relationships is far from being sufficient. The family is immersed in a systematic-taxonomic confusion. The necessity for a tool which enables species distinction and population characterization is evident. This paper aims to review the European Lymnaeidae basing on the second internal transcribed spacer ITS-2 of the nuclear ribosomal DNA. The ITS-2 sequences of 66 populations of 13 European and 1 North A…
Lymnaea cousinni (Gastropoda: Lymnaeidae) as transmitter of fascioliasis
2007
Dear Editor,In the article entitled “First report of Lymnaea cou-sini Jousseaume, 1887 naturally infected with Fasciolahepatica (Linnaeus, 1758) (Trematoda: Digenea) inMachachi, Ecuador” recently published by AngelVillavicencio A and Mauricio Carvalho de Vasconcellosin Memorias do Instituto Oswaldo Cruz (vol. 100, is-sue 7, pages 735-737, November 2005), it is stated thattheir finding in Ecuador represents the first report ofspecimens of this lymnaeid species naturally infectedby the liver fluke. However, it is well known from longago that this species acts as intermediate host of fascio-liasis in Andean countries. In the first half of the lastcentury, Brumpt et al. (1939-1940) already demo…
Fasciola hepatica phenotypic characterization in Andean human endemic areas: Valley versus altiplanic patterns analysed in liver flukes from sheep fr…
2011
Fascioliasis is a zoonotic parasitic disease caused by Fasciola hepatica and Fasciola gigantica. Of both species, F. hepatica is the only one described in the Americas, mainly transmitted by lymnaeid snail vectors of the Galba/. Fossaria group. Human fascioliasis endemic areas are mainly located in high altitude areas of Andean countries. Given the necessity to characterize F. hepatica populations involved, the phenotypic features of fasciolid adults infecting sheep present in human fascioliasis endemic areas were analysed in the Cajamarca Valley and Mantaro Valley (valley transmission patterns) and the northern Bolivian Altiplano (altiplanic transmission pattern). A computer image analysis…
Miracidial infectivity of Hypoderaeum conoideum (Trematoda: Echinostomatidae): differential susceptibility of two lymnaeid species.
1999
A study was made of the infectivity of Hypoderaeum conoideum miracidia to a range of laboratory-reared specimens of freshwater snail species (Lymnaea peregra, L. corvus, Physella acuta, and Gyraulus chinensis) that coexist with the parasite in the same natural habitat. L. peregra and L. corvus were found to be equally susceptible to the parasite when specimens of each snail species were singly exposed to miracidia. However, when miracidia could choose either lymnaeid species, they showed a high degree of specificity toward L. peregra. The results obtained suggest that H. conoideum miracidia are capable of distinguishing among these lymnaeids in their orientation to the host. This indicates …