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

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

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

Genetic diversity and relationships of the liver fluke Fasciola hepatica (Trematoda) with native and introduced definitive and intermediate hosts

Fasciolosis is a worldwide spread parasitosis mainly caused by the trematode Fasciola hepatica. This disease is particularly important for public health in tropical regions, but it can also affect the economies of many developed countries due to large infections in domestic animals. Although several studies have tried to understand the transmission by studying the prevalence of different host species, only a few have used population genetic approaches to understand the links between domestic and wildlife infections. Here, we present the results of such genetic approach combined with classical parasitological data (prevalence and intensity) by studying domestic and wild definitive hosts from Camargue (southern France) where fasciolosis is considered as a problem. We found 60% of domestic hosts (cattle) infected with F. hepatica but lower values in wild hosts (nutria, 19%; wild boars, 4.5%). We explored nine variable microsatellite loci for 1,148 adult flukes recovered from four different populations (non-treated cattle, treated cattle, nutria and wild boars). Populations from the four groups differed, though we found a number of migrants particularly non-treated cattle and nutria. Overall, we detected 729 different multilocus genotypes (from 783 completely genotyped individuals) and only 46 genotypes repeated across samples. Finally, we experimentally infected native and introduced intermediate snail hosts to explore their compatibility with F. hepatica and assess the risks of fasciolosis expansion in the region. The introduced species Galba truncatula and Pseudosuccinea columella attained the higher values of overall compatibility in relation to the European species. However, concerning the origin, sympatric combinations of G. truncatula were more compatible (higher prevalence, intensity and survival) than the allopatric tested. According to our results, we should note that the assessment of epidemiological risks cannot be limited to a single host–parasite system, but should focus on understanding the diversity of hosts in the heterogeneous environment through space and time.Fil: Vázquez, Antonio A.. Instituto de Medicina Tropical “Pedro Kourí”; Cuba. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; FranciaFil: Sabourin, Emeline. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Alda, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados I; Argentina. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Leroy, Clémentine. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Leray, Carole. Institut de Recherche de la Tour du Valat; FranciaFil: Carron, Eric. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Mulero, Stephen. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; Francia. Université de Perpignan Via Domitia; FranciaFil: Caty, Céline. Institut de Recherche de la Tour du Valat; FranciaFil: Hasfia, Sarah. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Boisseau, Michel. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Saugné, Lucas. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Pineau, Olivier. Institut de Recherche de la Tour du Valat; FranciaFil: Blanchon, Thomas. Institut de Recherche de la Tour du Valat; FranciaFil: Alba, Annia. Instituto de Medicina Tropical “Pedro Kourí”; Cuba. Università di Corsica Pasquale Paoli; FranciaFil: Faugère, Dominique. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; FranciaFil: Vittecoq, Marion. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; Francia. Institut de Recherche de la Tour du Valat; FranciaFil: Hurtrez Boussès, Sylvie. Centre National de la Recherche Scientifique; Francia. Université Montpellier II; Franci

Is the small clutch size of a Corsican blue tit population optimal?

International audienceIn an attempt to test predictions of the optimisation hypothesis of life history traits in birds, we estimated ®tness consequences of brood size manipulations. Experiments were carried out over a period of 4 years in a Mediterranean population of blue tits Parus caeruleus which is confronted with a particular set of environmental constraints. Eects of brood size manipulation were investigated in relation to year-toyear variation in environmental conditions, especially caterpillar abundance. There was a strong variation in the eects of brood size manipulation depending on year. Most eects were on ospring quality (¯edging mass, tarsus length). The absolute number of recruits did not signi®cantly dier among categories (reduced, control, enlarged broods) but varied considerably among years. Females recruited from enlarged broods were of lower quality, started to breed later and laid fewer eggs than those recruited from control and reduced broods. Neither parental survival nor reproductive performances of adults in year n + 1 was aected by brood size manipulation in year n. Thus there was no evidence for a cost of reproduction in this population. Since the number of recruits did not depend on brood size manipulation (recruitment rates were higher in reduced broods), but recruits from reduced broods were of better quality compared with other groups, we conclude that adults lay a clutch that is larger than that which is predicted by the optimisation hypothesis. Producing more young could incur some penalties because ospring from large broods are of lower quality and less likely to recruit in the population. Two possible reasons why decision rules in this population seem to be suboptimal are discussed

Parasite intensity is driven by temperature in a wild bird

International audienceThe rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change