Life tables of freshwater snails of the genus Biomphalaria (B. glabrata, B. alexandrina, B. straminea) and of one of its competitors Melanoides tuberculata under laboratory conditions

International audienceLife tables of several strains of Biomphalariea glabrata, B. alexandreina and B. straminea have been established under laboratory conditions and compared with that of Malanoides tuberculata, a prosobranch snail used as a competitor of snail vectors of schistosomiasis in experiments of biological control. Results indicate a grat range of intraspecific and interspecific variation within the Biomphalaria and a quite distinct demographic strategy of M. tuberculata

Isolation, characterization and population-genetic analysis of microsatellite loci in the freshwater snail <i>Galba cubensis</i> (Lymnaeidae)

The freshwater snail Galba cubensis (Pfeiffer, 1839) has a large distribution in the Americas. Despite being an intermediate host of Fasciola hepatica - the trematode causing fasciolosis in livestock and humans - its population genetics have never been studied. We isolated and characterized 15 microsatellite loci in G. cubensis to evaluate its genetic diversity, population-genetic structure and mating system. We tested the microsatellite loci in 359 individuals from 13 populations of G. cubensis from Cuba, Guadeloupe, Martinique, Puerto Rico, Venezuela, Colombia and Ecuador. We also tested cross-amplification in three closely related species: G. truncatula, G. viator and G. neotropica. We found that G. cubensis has a similar population structure to other selfing lymnaeids that live in temporary habitats: low genetic diversity, large departure from Hardy-Weinberg equilibrium, marked population structure and high selfing rate. We found that seven and six loci amplified in G. truncatula and G. viator, respectively, and that all 15 loci amplified in G. neotropica. This last finding suggests a close relatedness between G. cubensis and G. neotropica, probably being conspecific and synonymous. This new set of microsatellite markers will be a useful tool to study the genetic diversity of this snail species across a large geographical range and, consequently, to understand the emergence and re-emergence of fasciolosis in the Americas.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

Bridging gaps in the molecular phylogeny of the Lymnaeidae (Gastropoda: Pulmonata), vectors of Fascioliasis

<p>Abstract</p> <p>Background</p> <p>Lymnaeidae snails play a prominent role in the transmission of helminths, mainly trematodes of medical and veterinary importance (<it>e.g</it>., <it>Fasciola </it>liver flukes). As this family exhibits a great diversity in shell morphology but extremely homogeneous anatomical traits, the systematics of Lymnaeidae has long been controversial. Using the most complete dataset to date, we examined phylogenetic relationships among 50 taxa of this family using a supermatrix approach (concatenation of the 16 S, ITS-1 and ITS-2 genes, representing 5054 base pairs) involving both Maximum Likelihood and Bayesian Inference.</p> <p>Results</p> <p>Our phylogenetic analysis demonstrates the existence of three deep clades of Lymnaeidae representing the main geographic origin of species (America, Eurasia and the Indo-Pacific region). This phylogeny allowed us to discuss on potential biological invasions and map important characters, such as, the susceptibility to infection by <it>Fasciola hepatica </it>and <it>F. gigantica</it>, and the haploid number of chromosomes (n). We found that intermediate hosts of <it>F. gigantica </it>cluster within one deep clade, while intermediate hosts of <it>F. hepatica </it>are widely spread across the phylogeny. In addition, chromosome number seems to have evolved from n = 18 to n = 17 and n = 16.</p> <p>Conclusion</p> <p>Our study contributes to deepen our understanding of Lymnaeidae phylogeny by both sampling at worldwide scale and combining information from various genes (supermatrix approach). This phylogeny provides insights into the evolutionary relationships among genera and species and demonstrates that the nomenclature of most genera in the Lymnaeidae does not reflect evolutionary relationships. This study highlights the importance of performing basic studies in systematics to guide epidemiological control programs.</p

Isolation, characterization and population-genetic analysis of microsatellite loci in the freshwater snail <i>Galba cubensis</i> (Lymnaeidae)

The freshwater snail Galba cubensis (Pfeiffer, 1839) has a large distribution in the Americas. Despite being an intermediate host of Fasciola hepatica - the trematode causing fasciolosis in livestock and humans - its population genetics have never been studied. We isolated and characterized 15 microsatellite loci in G. cubensis to evaluate its genetic diversity, population-genetic structure and mating system. We tested the microsatellite loci in 359 individuals from 13 populations of G. cubensis from Cuba, Guadeloupe, Martinique, Puerto Rico, Venezuela, Colombia and Ecuador. We also tested cross-amplification in three closely related species: G. truncatula, G. viator and G. neotropica. We found that G. cubensis has a similar population structure to other selfing lymnaeids that live in temporary habitats: low genetic diversity, large departure from Hardy-Weinberg equilibrium, marked population structure and high selfing rate. We found that seven and six loci amplified in G. truncatula and G. viator, respectively, and that all 15 loci amplified in G. neotropica. This last finding suggests a close relatedness between G. cubensis and G. neotropica, probably being conspecific and synonymous. This new set of microsatellite markers will be a useful tool to study the genetic diversity of this snail species across a large geographical range and, consequently, to understand the emergence and re-emergence of fasciolosis in the Americas.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

An outbreak of canine schistosomiasis in Utah: Acquisition of a new snail host (Galba humilis) by Heterobilharzia americana, a pathogenic parasite on the move

Parasites with complex life cycles engaging multiple host species living among different environments well-exemplify the value of a cross-cutting One Health approach to understanding fundamental concerns like disease emergence or spread. Here we provide new information regarding a pathogenic schistosome trematode parasite of both wild and domestic mammals that has recently expanded its known range from mesic/wet environments of the southeastern United States to the arid southwest. In 2018, 12 dogs living near a man-made pond in Moab, Utah, were found positive for Heterobilharzia americana, the most westerly report of this endemic North American schistosome, and the first from Utah. Raccoon scats collected near the pond were positive for H. americana eggs, and snails living near the pond´s water line identified as Galba humilis shed H. americana cercariae, the first indication of natural infections in this widespread North American snail species. The susceptibility of G. humilis to H. americana was confirmed experimentally. Our studies support the existence of two variants of H. americana and emphasize the need for further investigations of lymnaeids and their compatibility with H. americana, to better define the future potential for its spread. Capture of a new species of intermediate host vector snail and construction of man-made habitats suitable for this snail have created the potential for a much more widespread animal health problem, especially for dogs and horses. H. americana will prove difficult to control because of the role of raccoons in maintaining transmission and the amphibious habits of the snail hosts of this pathogenic schistosome.Fil: Loker, Eric S.. University of New Mexico; Estados UnidosFil: Dolginow, Scott Z.. Mill Creek Animal Hospital; Estados UnidosFil: Pape, Suzanne. Mill Creek Animal Hospital; Estados UnidosFil: Topper, Colin D.. No especifíca;Fil: Alda, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Pointier, Jean Pierre. Centre National de la Recherche Scientifique; FranciaFil: Ebbs, Erika T.. State University of New York; Estados UnidosFil: Sanchez Herrera, Melissa. University of New Mexico; Estados UnidosFil: Verocai, Guilherme G.. Texas A&M University; Estados UnidosFil: DeJong, Randall J.. Calvin University; Estados UnidosFil: Brant, Sara V.. University of New Mexico; Estados UnidosFil: Laidemitt, Martina R.. University of New Mexico; Estados Unido

First report of Galba cubensis (Gasteropoda: Lymnaeidae) in Ecuador, host of Fasciola hepatica potential in rice fields of the ecuadorian coast

Las especies invasoras representan una amenaza para la salud humana y los alimentos, especialmente cuando estas especies son introducidas a nuevos hábitats y transmiten parásitos a los seres humanos o a los animales domésticos. El molusco Galba cubensis es el principal hospedador intermediario de Fasciola hepatica – agente causal de la fascioliasis – y está distribuido desde Norte América hasta Sur América. Sin embargo, en Ecuador G. cubensis no se había reportado hasta la presente publicación. En un inventario completo de caracoles pulmonados de agua dulce llevadas a cabo en 1965, las dos únicas especies de la familia Lymnaeidae reportadas fueron el caracol invasor Pseudosuccinea columella y el caracol nativo Galba cousini. Se realizó una búsqueda malacológica en arrozales de la provincia del Guayas, Ecuador, entre 2013 y 2015 y encontramos por primera vez G. cubensis en el país. A continuación, se estudió la morfología de estos caracoles para identifcar la especie. Llegando a la conclusión de que G. cubensis es una especie invasora que se ha introducido al Ecuador en los últimos 50 años. También anticipamos que esta especie podría estar transmitiendo fascioliasis en la región litoral del Ecuador.Biological invasions represent a threat to human and food health when the species introduced transmit parasites to humans or domestic animals. Galba cubensis is the main snail host of Fasciola hepatica—the agent of fasciolosis—and has a current range from North to South America. Nonetheless, in Ecuador G. cubensis has not been reported until now. In a complete inventory of freshwater pulmonate snails carried out in 1965, the only two lymnaeid species reported were the invasive snail Pseudosuccinea columella and the native snail Galba cousini. We carried out a malacological survey in rice felds of the Guayas Province, Ecuador, between 2013 and 2015 and we found for the frst time G. cubensis in this country. We conclude that G. cubensis is an invasive species that has been introduced to Ecuador in the past 50 years. We also anticipate that this species could be spreading fasciolosis from the higher and Andean region to the lower and tropical region of Ecuador.Centro de Estudios Parasitológicos y de Vectore

First report of Galba cubensis (Gasteropoda: Lymnaeidae) in Ecuador, host of Fasciola hepatica potential in rice fields of the ecuadorian coast

Las especies invasoras representan una amenaza para la salud humana y los alimentos, especialmente cuando estas especies son introducidas a nuevos hábitats y transmiten parásitos a los seres humanos o a los animales domésticos. El molusco Galba cubensis es el principal hospedador intermediario de Fasciola hepatica – agente causal de la fascioliasis – y está distribuido desde Norte América hasta Sur América. Sin embargo, en Ecuador G. cubensis no se había reportado hasta la presente publicación. En un inventario completo de caracoles pulmonados de agua dulce llevadas a cabo en 1965, las dos únicas especies de la familia Lymnaeidae reportadas fueron el caracol invasor Pseudosuccinea columella y el caracol nativo Galba cousini. Se realizó una búsqueda malacológica en arrozales de la provincia del Guayas, Ecuador, entre 2013 y 2015 y encontramos por primera vez G. cubensis en el país. A continuación, se estudió la morfología de estos caracoles para identifcar la especie. Llegando a la conclusión de que G. cubensis es una especie invasora que se ha introducido al Ecuador en los últimos 50 años. También anticipamos que esta especie podría estar transmitiendo fascioliasis en la región litoral del Ecuador.Biological invasions represent a threat to human and food health when the species introduced transmit parasites to humans or domestic animals. Galba cubensis is the main snail host of Fasciola hepatica—the agent of fasciolosis—and has a current range from North to South America. Nonetheless, in Ecuador G. cubensis has not been reported until now. In a complete inventory of freshwater pulmonate snails carried out in 1965, the only two lymnaeid species reported were the invasive snail Pseudosuccinea columella and the native snail Galba cousini. We carried out a malacological survey in rice felds of the Guayas Province, Ecuador, between 2013 and 2015 and we found for the frst time G. cubensis in this country. We conclude that G. cubensis is an invasive species that has been introduced to Ecuador in the past 50 years. We also anticipate that this species could be spreading fasciolosis from the higher and Andean region to the lower and tropical region of Ecuador.Centro de Estudios Parasitológicos y de Vectore

Freshwater Molluscs of Venezuela and their Medical and Veterinary Importance

International audienceThe objective of this book is to bridge a gap in the freshwater malacology of Venezuela which includes native, endemic and introduced species. A special effort has been set on species playing the role of intermediate hosts of important trematodiasis infecting cattle and humans in Venezuela. Gastropods are the most important group of molluscs including 49 species of which 11 may be considered as endemic, 28 as native and 10 as introduced. Bivalves include 16 species of which 3 may be considered as endemic, 11 as native and 2 as introduced. A state of the art is presented for each species: morphological description including shell morphology, anatomy of the reproductive system, phylogenetic data and genetic diversity when available, type of habitat and ecology. Since many of the treated species are distributed in large parts of Southern and Central America this book delivers an useful tool for the determination of freshwater molluscs in most parts of Central and Southern America

El control biológico de los moluscos hospedadores intermediarios de los esquistosomas: el ejemplo de la región del Caribe

El control de los hospederos intermediarios de la esquistosomosis es un componente indispensable de la lucha integrada contra esta parasitosis. Los productos químicos de acción molusquicida han sido y continúan siendo utilizados de forma extensiva, para intentar eliminar al hospedero intermediario. Sin embargo, estos productos son caros y requieren ser aplicados repetidamente con la necesidad de disponer de una compleja y costosa estructura organizativa. Además, la acción de estos productos no es específica y los mismos son tóxicos para otros organismos como peces y crustáceos. Por lo anterior se ha impuesto la búsqueda de otras alternativas al control de moluscos y, entre ellas, el control biológico ha sido el objeto de importantes investigaciones en el transcurso de las últimas dos décadas (ver las revisiones de la O.M.S., 1984; Madsen, 1990; 1995; Pointier y Giboda, 1999; Pointier y Jourdane, 2000). El presente artículo tiene por objetivo exponer los principales resultados que han sido obtenidos en la región del Caribe