DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with description of L. meridensis n. sp. (Gastropoda: Lymnaeidae)

<p>Abstract</p> <p>Background</p> <p>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 <it>Lymnaea cousini</it>, <it>L. bogotensis </it>and <it>L. ubaquensis</it>, 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 <it>cox</it>1 gene.</p> <p>Results</p> <p>The conserved 5.8S rDNA sequence corroborated that no pseudogenes are involved in the numerous non-microsatellite/minisatellite-related indels appearing between the ITS-2 and ITS-1 sequences when comparing different <it>L. cousini </it>- <it>L. bogotensis </it>populations. Sequence analyses and phylogenetic reconstruction methods including other lymnaeid vector species show that (i) <it>L. bogotensis </it>is a synonym of <it>L. cousini</it>, (ii) <it>L. ubaquensis </it>is a synonym of <it>Pseudosuccinea columella</it>, and (iii) populations of <it>L. cousini </it>hitherto known from Venezuelan highlands indeed belong to a new species for which the name <it>L. meridensis </it>n. sp. is proposed. This new species is described and a complete phenotypic differentiation provided.</p> <p>Conclusions</p> <p>ITS-2, ITS-1 and <it>cox</it>1 prove to be good markers for specimen classification and haplotype characterisation of these morphologically similar lymnaeids in endemic areas. Analysis of the 18S gene and phylogenetic reconstructions indicate that <it>L. cousini </it>and <it>L. meridensis </it>n. sp. cluster in an evolutionary line different from the one of <it>P. columella</it>, despite their external resemblance. This suggests an evolutionary phenotypic convergence related to similar environments and which has given rise to frequent specimen misclassification. Body size and phylogenetic relationships of <it>L. meridensis </it>n. sp. with well-known vectors as <it>Lymnaea cousini </it>and <it>P. columella</it>, as well as with <it>Galba</it>/<it>Fossaria </it>species, suggest that the new species may participate in disease transmission to both animals and humans in altitude areas during the yearly window in which temperatures are higher than the <it>F. hepatica </it>minimum development threshold. The involvement of <it>L. cousini </it>and <it>P. columella </it>in the transmission and geographical/altitudinal distribution of fascioliasis in these Andean countries is analysed.</p

West Nile virus in Spain: Forecasting the geographical distribution of risky areas with an ecological niche modelling approach

West Nile virus (WNV), a well-known emerging vector-borne arbovirus with a zoonotic life cycle, represents a threat to both public and animal health. Transmitted by ornithophilic mosquitoes, its transmission is difficult to predict and even more difficult to prevent. The massive and unprecedented number of human cases and equid outbreaks in Spain during 2020 interpellates for new approaches. For the first time, we present an integrate analysis from a niche perspective to provide an insight to the situation of West Nile disease (WND) in Spain. Our modelling approach benefits from the combined use of global occurrence records of outbreaks of WND in equids and of its two alleged main vectors in Spain, Culex pipiens and Cx. perexiguus. Maps of the climatic suitability for the presence of the two vectors species and for the circulation of WNV are provided. The main outcome of our study is a map delineating the areas under certain climatic risk of transmission. Our analyses indicate that the climatic risk of transmission of WND is medium in areas nearby the south Atlantic coastal area of the Cadiz Gulf and the Mediterranean coast, and high in southwestern Spain. The higher risk of transmission in the basins of the rivers Guadiana and Guadalquivir cannot be attributed exclusively to the local abundance of Cx. pipiens, but could be ascribed to the presence and abundance of Cx. perexiguus. Furthermore, this integrated analysis suggests that the WNV presents an ecological niche of its own, not fully overlapping the ones of its hosts or vector, and thus requiring particular environmental conditions to succeed in its infection cycle.Fil: Cuervo Bustamante, Pablo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad de Valencia; EspañaFil: Artigas, Patricio. Universidad de Valencia; EspañaFil: Mas-Coma, Santiago. Universidad de Valencia; EspañaFil: Bargues, María Dolores. Universidad de Valencia; Españ

Aplicação do conceito One Health na área hiperendêmica de fasciolíase humana do Altiplano Boliviano: biologia dos limneídeos, dinâmica populacional, microecologia e influência de fatores climáticos

Fascioliasis is a freshwater snail-borne zoonotic disease. The Northern Bolivian Altiplano is a very high altitude endemic area where the highest human prevalences and intensities have been reported. Preventive chemotherapy by treatment campaigns is yearly applied. However, liver fluke infection of cattle, sheep, pigs and donkeys assures endemicity and consequent human infection and re-infection risks. A One Health action has therefore been implemented. Activity concerns lymnaeid vectors and environment diversity. Studies included growth, egg-laying and life span in laboratory-reared lymnaeids. Different habitat types and influencing factors were assessed. All populations proved to belong to Galba truncatula by rDNA sequencing. Analyses comprised physico-chemical characteristics and monthly follow-up of water temperature, pH and quantity, and lymnaeid abundance and density. Population dynamics in the transmission foci differed. Mean environmental temperature was lower than fluke development minimum temperature threshold, but water temperature was higher, except during winter. A two generations/year pattern appeared in permanent water habitats, and one generation/year pattern in habitats drying out for months. The multidisciplinary control measures can be extended from one part of the endemic area to another. These studies, made for the first time at very high altitude, constitute a baseline useful for fascioliasis control in other countries.A fasciolíase é uma doença zoonótica transmitida para os humanos por formas evolucionárias de Fasciola hepatica oriundas de limneídeos infectados. O Altiplano Boliviano Norte é uma área endêmica de altitude muito alta, onde foram relatadas as maiores prevalências e intensidades em infecções humanas. A quimioterapia preventiva por campanhas de tratamento é aplicada anualmente. No entanto, infecção por Fasciola hepatica em bovinos, ovelhas, suínos e asininos garante endemicidade e consequentes riscos de infecção e reinfecção humana. Portanto, ações norteadas no conceito “One Health” foram implementadas. As atividades envolveram os limneídeos e a avaliação da diversidade de ambientes. Os estudos incluíram o crescimento, postura de ovos e expectativa de vida de limneídeos criados em laboratório, bem como a avaliação da influência dos diferentes hábitats. Todas as populações foram identificadas como Galba truncatula por meio do sequenciamento de rDNA. As análises incluíram características físico-químicas e acompanhamento mensal da temperatura, pH, quantidade da água, abundância e densidade de limneídeos. A dinâmica populacional nos focos de transmissão diferiu. A temperatura ambiente média foi mais baixa do que o limite mínimo de temperatura do desenvolvimento do helminto, mas a temperatura da água foi mais alta, exceto durante o inverno. Um padrão de duas gerações/ano apareceu em hábitats com água permanente, enquanto um padrão de uma geração/ano foi observado em hábitats que ficam secos durante meses. Os resultados permitem concluir que as medidas multidisciplinares de controle podem ser estendidas de uma parte da área endêmica para outra. Esses estudos, realizados pela primeira vez em altitudes muito elevadas, constituem uma base útil e extrapolável para o controle da fasciolíase.Fil: Bargues, María Dolores. Universidad de Valencia; EspañaFil: Angles, René. Universidad Mayor de San Andrés; BoliviaFil: Coello, José. No especifíca;Fil: Artigas, Patricio. Universidad de Valencia; EspañaFil: Funatsu, Ilra Renata. Universidad de Valencia; EspañaFil: Cuervo Bustamante, Pablo Fernando. Universidad de Valencia; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Buchon, Paola. Universidad Mayor de San Andrés; BoliviaFil: Mas-Coma, Santiago. Universidad de Valencia; Españ

Domestic pig prioritized in One Health action against fascioliasis in human endemic areas : experimental assessment of transmission capacity and epidemiological evaluation of reservoir role.

The Northern Bolivian Altiplano is the human fascioliasis hyperendemic area where the highest prevalences and intensities in humans have been reported. Preventive chemotherapy was implemented in the last ten years. Surveillance showed high human infection and re-infection rates in between the annual triclabendazole monodose treatments. A complementary One Health control action was launched to decrease the infection risk. Among the multidisciplinary axes, there is the need to establish animal reservoir species priorities for a more efficient control. Laboratory and field studies were performed for the first time to assess the Fasciola hepatica transmission capacity of the pig and its potential reservoir role. The experimental follow-up of altiplanic pig isolates through altiplanic Galba truncatula snail vector isolates were performed at different miracidial doses and different day/ night temperatures. Experiments included egg embryonation, miracidial infectivity, lymnaeid snail infection, intramolluscan larval development, cercarial production, chronobiology of the cercarial shedding, vector survival to infection, metacercarial infectivity of mammal host, and adult stage development. Surveys included the assessment of prevalence, intensity, egg measurements and egg shedding rates in nature. Pig contribution was evaluated by comparing with the main altiplanic reservoirs sheep and cattle. Results demonstrated that the pig assures the whole F. hepatica life cycle and participates in its transmission in this area. The fast egg embryonation, high cercarial production, long multi-wave shedding chronobiological pattern in monomiracidial infections at permanent 20 ◦C temperature, and the high daily egg outputs per pig are worth mentioning. The high infection risk suggests early infection of freely running piglets and evolutionary long-term adaptation of the liver fluke to this omnivorous mammal, despite its previously evoked resistance or non-suitability. Genetic, physiological and immune similarities with humans may also underlie the parasite adaptation to humans in this area. The pig should be accordingly included for appropriate control measures within a One Health action against human fascioliasis. The pig should henceforth be considered in epidemiological studies and control initiatives not only in fascioliasis endemic areas with human infection risk on other Andean countries, but also in rural areas of Latin America, Africa and Asia where domestic pigs are allowed to run freely

Clinical impact of fascioliasis in equines from andean zones of Mendoza province, Argentina

En las zonas andinas los equinos son importantes como animales de transporte y carga (a veces el único medio) además de realizar actividades deportivas y recreativas. La fascioliasis en equinos ha sido descrita en varios países de todos los continentes. Investigaciones realizadas por el CIPAR hallaron prevalencias del 50% en caballos de La Rioja, 19,4% en mulas de Uspallata y del 42,8% de caballos y 100% de asnos en Lujan de Cuyo. En Egipto y Bolivia, el asno es el segundo reservorio en importancia luego de los rumiantes. Sin embargo, otros estudios de infecciones experimentales en caballos, no lograron reproducir la enfermedad. El conocimiento actual acerca de esta parasitosis en equinos es escaso

Clinical burden and epidemiological characteristics of fascioliasis in horses of andean regions of Mendoza province

Fasciola hepatica es un trematodo zoonótico, cosmopolita, con reservorios animales, domésticos y silvestres. En Mendoza, es prevalente en rumiantes y en equinos, la ocurrencia va del 19 al 100%. El caballo no es considerado reservorio de F. hepatica. La distomatosis equina fue estudiada en varios países, pero hay información escasa sobre su presentación clínica en caballos. El objetivo de este estudio fue caracterizar hematología y química sérica de caballos parasitados por Fasciola hepatica, y a los animales infectados

Riesgo zoonótico relacionado con la presencia de Lymnea neotropica en la Provincia De Mendoza, Argentina

La provincia de Mendoza en Argentina tiene zonas de alta endemia de fascioliasis en el ganado y registro de casos humanos, principalmente en regiones montañosas de altitud superior a los 1500 m snm. Es en los valles andinos donde mejor se desarrollan los vectores, tanto Lymnaea viatrix como el introducido Galba truncatula. La zona de baja altitud en la llanura esdonde se encuentran los oasis que concentran el 95% de la población de la provincia, donde no suelen reportarse casos de fascioliasis. Recientemente se detecto un brote en el ganado a baja altitud (902 m snm)