Molecular characterization of cryptic and sympatric lymnaeid species from the Galba/Fossaria group in Mendoza Province, Northern Patagonia, Argentina

Background Freshwater lymnaeid snails can act as the intermediate hosts for trematode parasites such as the liver fluke Fasciola hepatica, that cause significant economic and biomedical burden worldwide, particularly through bovine fascioliasis. Transmission potential is tightly coupled to local compatibility with snail hosts, so accurate identification of lymnaeid species is crucial for understanding disease risk, especially when invasive species are encountered. Mendoza Province, in Argentina, is a center of livestock production and also an area of endemic fascioliasis transmission. However, the distribution of lymnaeid species in the region is not well known. Methods This study examined lymnaeid snails from seven localities in the Department of Malarguë, Mendoza Province, using morphological and molecular analyses and also describing ecological variables associated with snail presence. Results While morphological characters identified two species of lymnaeid, Galba truncatula and G. viatrix, molecular data revealed a third, cryptic species, G. neotropica, which was sympatric with G. viatrix. G. truncatula was exclusively found in high altitude (>1900 meters above sea level [masl]) sites, whereas mixed G. neotropica/G. viatrix localities were at middle elevations (1300–1900 masl), and G. viatrix was found alone at the lowest altitude sites (<1300 masl). Phylogenetic analysis using two mitochondrial markers revealed G. neotropica and G. viatrix to be closely related, and given their morphological similarities, their validities as separate taxonomic entities should be questioned. Conclusions This study highlights the need of a robust taxonomic framework for the identification of lymnaeid snails, incorporating molecular, morphological and ecological variables while avoiding nomenclature redundancy. As the three species observed here, including one alien invasive species, are considered hosts of varying susceptibility to Fasciola parasites, and given the economic importance of fascioliasis for livestock production, this research has critical importance for the ultimate aim of controlling disease transmission

Presence of pseudosuccinea columella naturally infested by fasciola hepatica in Santo Tomé (Corrientes, Argentina)

Fil: Moriena, R. A. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina.Fil: Álvarez, José Dario. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina.Fil: Pietrokovsky, Silvia M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Rubel, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Prepelitchi, Lucila. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Racioppi, Oscar. Universidad de Buenos Aires.Fil: Wisnivesky, C. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina.La fasciolosis es una enfermedad producida por Fasciola hepatica. Esta parasitosis produce grandes pérdidas económicas en el ganado bovino de la Provincia de Corrientes, Argentina, y también tiene carácter zoonótico. En el norte de la Provincia, Pseudosuccinea columella es el caracol involucrado en la transmisión de la enfermedad. El objetivo del presente trabajo fue ampliar los datos sobre la distribución de P. columella y su infestación natural por F. hepatica en la Provincia de Corrientes. Se recolectaron caracoles en un establecimiento ganadero del Departamento de Santo Tomé, al nordeste de la Provincia, que fueron identificados taxonómicamente, medidos y disecados para verificar la presencia de cercarias de F. hepatica. Los 115 caracoles recolectados fueron identificados como P. columella. La longitud de la conchilla varió entre 0,8–21,3 mm, con una media de 10,0 mm. La prevalencia de caracoles naturalmente infestados por F. hepatica fue de 8 (7,4%) sobre 108 examinados. La presencia de P. columella en distintos departamentos del norte y nordeste de la Provincia de Corrientes y las altas prevalencias de infestación natural por F. hepatica registradas, indicarían el asentamiento de un ciclo de transmisión enzoótica en esta zona.Fasciolosis is a parasitic disease caused by Fasciola hepatica, that originates great economic losses in livestock production and is also considered a zoonosis. In Corrientes, northeastern Argentine, the snail Pseudosuccinea columella is involved in the transmission of the disease. The objective of this work is to provide with up–do–date data on the distribution and presence of naturally infested P. columella snails in this region. Snails were collected from a cattle farm in Santo Tomé, northeast of Corrientes. Snails were taxonomically classified, measured and examined for F. hepatica cercariaes. All 115 snails were identified as P. columella. Shell length ranged between 0.8–21.3 mm, with a mean of 10.0 mm. Prevalence of F. hepatica infestation was 8 (7.4%) over 108 snails. The presence of P. columella and the high prevalence values recorded for the northern and northeastern areas of Corrientes may indicate the establishment of an enzootic transmission cycle in the region

Galba truncatula Muller, 1774 (Pulmonata : Lymnaeidae) in Argentina: Presence and natural infection by Fasciola hepatica (Linnaeus, 1758) (Trematoda : Digenea)

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Relação entre Triatoma infestans, aves domésticas e o homem num povoado de Santiago del Estero, Argentina

Determinou-se a associação entre Triatoma infestans, aves domésticas e o homem no povoado de Trinidad, Santiago del Estero, Argentina. Para coletar triatomíneos foram realizadas quatro amostragens no peridomicílio de seis casas, utilizando-se o método de captura hora/homem (dezembro de 1991 a outubro de 1992). Os anexos foram classificados em antrópicos (onde o homem realiza atividades cotidianas) e não-antrópicos. Além disso, determinou-se o perfil alimentar dos barbeiros. De um total de 134 ecótopos investigados, 21% tinham T. infestans; 22% possuíam aves domésticas; e 54% eram antrópicos. Em 25% destes ecótopos foram encontradas aves e T. infestans simultaneamente. As aves foram os únicos animais domésticos associados com o T. infestans, sendo que esta relação só ocorreu nos ecótopos antrópicos. A proporção de ingestas em aves (61/146) foi altamente significativa. Em Trinidad não há galinheiros, utilizando-se, assim, os anexos entrópicos do peridomicílio como local para se construir os ninhos para as aves. tanto pelos elementos usados na preparação dos ninhos como pelo uso posterior dos mesmos, poder-se-ia estabelecer um fluxo periódico de barbeiros do intradomicílio para o peridomicílio, e vice-versa, através do transporte passivo. Esta relação estreita entre Triatoma infestans, aves domésticas e o homem, encontrada nos ecótopos antrópicos, onde também existem outros reservatórios de T. cruzi, como os cães, favorece a manutenção de colônias de barbeiros domiciliares e a transmissão da doença de Chagas ao homem

Ecological characteristics of Triatoma patagonica at the Southern limit of its distribution (Chubut, Argentina)

This study aimed at identifying the ecological characteristics of Triatoma patagonica Del Ponte 1929 (Hemiptera: Reduviidae) and evaluating the epidemiological importance of this species at its southernmost distribution limit. We carried out two surveys in the Province of Chubut, in summer and in spring, 1998. In each survey, we interviewed local health care agents for triatomine recognition and reports of the bugs, followed by entomological searches in houses and peridomestic and silvatic biotopes. The presence of T. patagonica was confirmed in two of the five localities indicated by interview. In agreement with previous studies, all these positive localities were east of the 11°C isotherm, within the Monte phytogeographic province. Triatomine abundance and infestation levels (in peridomiciles and peridomestic biotopes) were higher in summer than in spring, possibly reflecting adverse environmental conditions such as flood and cold winter weather. In the silvatic environment, we found three adult bugs under rocks in summer. In peridomestic sites bugs were only found associated with chickens, which were also the only blood meal source identified. Infection by Trypanosoma cruzi was not detected. We conclude that T. patagonica at its southernmost distribution limit does not represent a risk to public health due to its low abundance, lack of association with humans, and absence of T. cruzi infection