NUEVOS REGISTROS DE HELMINTOS PARÁSITOS DE PECES PIMELODIDAE, EN EL SISTEMA PARANÁ MEDIO (ARGENTINA)

Se describen los macroparásitos hallados en tractos intestinales de Pimelodus albicans (Valenciennes, 1840), P. maculatus La Cepède, 1803, Luciopimelodus pati (Valenciennes, 1836) y Pseudoplatystoma corruscans (Spix & Agassiz, 1829). Se amplía la distribución geográfica de varios parásitos que fueran citados para Sudamérica y se hallan por primera vez en Argentina: Procamallanus (Spirocamallanus) pimelodus Pinto, Fábio, Noronha & Rolas, 1974, citado para el río Paraná Superior (Brasil); y P. (S.) neocaballeroi (Caballero-Deloya, 1977), hallado en México. Se registran nuevos hospedadores para parásitos adultos ya descritos: P. corruscans para Thometrema overstreeti (Brooks, Mayes & Thorson, 1979) Lunaschi 1989; y P. maculatus para P. (S.) inopinatus Travassos, Artigas & Pereira, 1928. Los parásitos hallados en P. corruscans y L. pati constituyen aportes pioneros al conocimiento de la interacción en la región, ya que son escasos los estudios previos sobre los parásitos de estos pimelódidos de gran porte

HELMINTOS PARÁSITOS DE MICROPTERUS SALMOIDES (LACEPÉDE, 1802) UNA ESPECIE INVASORA EN BRASIL: UN CASO DE CO-INTRODUCCIÓN Y SPILLBACK

La perca americana, Micropterus salmoides (Lacepéde, 1802), es un pez centrarchido de América del Norte que ahora tiene una distribución global debido a introducciones extendidas por pesca deportiva. Su introducción en Brasil data de 1920, principalmente en las regiones del sur. Sabemos que M. salmoides ha generado una serie de impactos en los ecosistemas en que se ha establecido. Sin embargo, sus parásitos en Brasil son desconocidos. Esto genera la posibilidad de nuevas interacciones y potenciales impactos. Por tanto, el objetivo de este estudio fue analizar los parásitos de M. salmoides en cuatro reservorios de agua en el sur de Brasil, midiendo la prevalencia y la abundancia media en cada reservorio. Analizamos un total de 59 individuos de M. salmoides, 15 en cada reserva, con excepción de la reserva Capivari-Cachoeira, con 14 individuos. De los peces analizados, 91,5% estaban parasitados por 1567 parásitos pertenecientes a cuatro especies, tres nemátodos: Contracaecum sp. (86,4%) en larvas, Procamallanus (Procamallanus) peraccuratus Pinto, Fábio, Noronha y Rolas 1976 (6,7%) y Hysterothylacium brachyurum Ward & Magath 1917 (6,7%), y una especie de monogenoideo Onchocleidus principalis (Mizelle, 1936) (57,6 %). De estos resultados podemos concluir que el proceso de co-introducción y “spillback” aún está en etapas tempranas, en la mayoría de las veces por la baja diversidad de parásitos. Sin embargo, el monitoreo y las acciones de control son altamente recomendadas para controlar los impactos de infecciones por parásitos y promover actividades de mitigación y campañas de prevención

Nematodes as indicators of environmental changes in a river with different levels of anthropogenic impact

Abstract Considering that changes in the biodiversity of parasite communities can be used as indicators of ecosystem health, the aim of this study was to investigate the potential use of Geophagus brasiliensis parasites as bioindicators of environmental changes. We established three sample points in the Iguaçu River, each presenting different degrees of environmental impact. Out of the 69 G. brasiliensis specimens analyzed, 32 (46.3%) were parasitized by at least one parasite. We collected a total of 56 specimens of endoparasites belonging to the phylum Nematoda. Fishes collected in point 3 presented a significantly higher abundance of nematode species (moderately degraded) (Kruskal-Wallis2;69 = 8.62; p = 0.01) and species compositions between points were significantly different (F = 6.95, p = 0.002). No significant difference in relative condition factor (Kn) among the points (F2;66 = 2.54; p = 0.08) or correlation in Kn and abundance of nematodes (rs = 0.1; p = 0.4) were indicated. The results presented in this study indicate that the parasitic community of G. brasiliensis is characterized by low diversity in polluted locations, which explains the absence of certain parasite species and the occurrence of nematode species with varied responses to the pollution gradient

Phylogenetic position of Diplostomum spp. from New World herons based on complete mitogenomes, rDNA operons, and DNA barcodes, including a new species with partially elucidated life cycle

Diplostomum ardeae Dubois, 1969 has seldom been reported since its description from the great blue heron (Ardea herodias L., 1758) in the USA. Sequences obtained in this study from the barcode region of cytochrome c oxidase 1 (CO1) in diplostomids from black-crowned night heron (Nycticorax nycticorax (L., 1758)) in Puerto Rico matched data from D. ardeae from A. herodias in the type region. We also obtained DNA barcodes from morphologically similar diplostomids from a rufescent tiger heron (Tigrisoma lineatum (Boddaert, 1783)) and from metacercariae from eye lenses of Trachelyopterus galeatus (Linnaeus, 1766) from the Paraná River basin in Argentina and Brazil, respectively. Barcodes matched (97–100% identity) in these South American adult and larval specimens as well as in recently published sequences from metacercariae from 11 other siluriform fishes from the same region. Barcodes from the South American species, which we describe as Diplostomum lunaschiae n. sp., differed from those of D. ardeae by 7.2–9.8%, and the new species differs from D. ardeae in its size, pharynx:oral sucker length ratio, egg:body length ratio, and distribution of vitellaria. As in prior phylogenetic analysis of CO1 sequences, both D. ardeae and D. lunaschiae n. sp. were not associated with Diplostomum. In more character-rich analyses of nuclear rDNA and of mitochondrial genomes, D. ardeae was an early divergent member of clades of species of Diplostomum. Consequently, we continue to consider D. ardeae and D. lunaschiae n. sp. members of Diplostomum, in contrast to recent suggestions that these species may belong to a different genus.Facultad de Ciencias Naturales y Muse

DIVERSIDAD DE LOS NEMATODOS DE TETRA COLA ROJA ASTYANAX AFF. PARANAE (TELEOSTEI: CHARACIDAE) DE SITIOS CONTAMINADOS DE UN SISTEMA DE RÍO TROPICAL

Aquatic systems are affected by a great variety of anthropogenic activities that alter the water quality through the introduction of organic and inorganic pollutants, consequently impacting all trophic levels of a biological community. The relationship between parasite species diversity and organic pollution in the high Paraná River basin, Paraná, Brazil was investigated during two seasons (Winter and Summer) of 2011. A total of 114 red-tail-lambari (Astyanax aff. paranae Eigenmann, 1914) were sampled from a non-impacted location (Perobas Reserve) and from impacted regions (agricultural and urban regions, upstream and downstream the city of Campo Mourão, respectively). The nematode Spinitectus yorkei Travassos, Artigas & Pereira, 1928 was found on the preserved area, while the nematode Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 was found only on the severely polluted areas. The variability of the prevalence index suggests that the structure of the parasite community is affected at different ways by the same levels of pollutants on the water. The observed results assume that the alteration in parasite diversity can be related to increased organic pollution, and that the differences in the parasite community from different environments can be related to biotic stress.Los sistemas acuáticos se ven afectados por una gran variedad de actividades antropogénicas que alteran la calidad del agua a través de la introducción de contaminantes orgánicos e inorgánicos, por consiguiente, afectan a todos los niveles de la comunidad biológica. De esta forma, la relación entre la diversidad de especies de parásitos y la contaminación orgánica en la cuenca del alto Paraná, Paraná, Brasil, se investigó en dos temporadas (invierno y verano) de 2011. Un total de 114 tetra cola roja (Astyanax aff. paranae Eigenmann, 1914) se muestrearon en un sitio no impactado (Reserva Perobas) y en regiones impactadas (zonas agrícolas y urbanas, aguas arriba y aguas abajo de la ciudad de Campo Mourão, respectivamente). El nematodo Spinitectus yorkei Travassos, Artigas y Pereira, 1928 se encuentran en la zona protegida, mientras que el nematodo Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas y Pereira, 1928 se encuentran sólo en las zonas gravemente contaminadas. La variabilidad del índice de prevalencia sugiere que la estructura de la comunidad de parásitos se ve afectada en diferentes formas por el mismo nivel de contaminantes en el agua. Los resultados observados asumen que la alteración en la diversidad parasitaria puede estar relacionada con el aumento de la contaminación orgánica, y que la respuesta de la comunidad de parásitos a las tensiones ambientales puede ser utilizada como bioindicadora

Phylogenetic position of Diplostomum spp. from New World herons based on complete mitogenomes, rDNA operons, and DNA barcodes, including a new species with partially elucidated life cycle

Diplostomum ardeae Dubois, 1969 has seldom been reported since its description from the great blue heron (Ardea herodias L., 1758) in the USA. Sequences obtained in this study from the barcode region of cytochrome c oxidase 1 (CO1) in diplostomids from black-crowned night heron (Nycticorax nycticorax (L., 1758)) in Puerto Rico matched data from D. ardeae from A. herodias in the type region. We also obtained DNA barcodes from morphologically similar diplostomids from a rufescent tiger heron (Tigrisoma lineatum (Boddaert, 1783)) and from metacercariae from eye lenses of Trachelyopterus galeatus (Linnaeus, 1766) from the Paraná River basin in Argentina and Brazil, respectively. Barcodes matched (97–100% identity) in these South American adult and larval specimens as well as in recently published sequences from metacercariae from 11 other siluriform fishes from the same region. Barcodes from the South American species, which we describe as Diplostomum lunaschiae n. sp., differed from those of D. ardeae by 7.2–9.8%, and the new species differs from D. ardeae in its size, pharynx:oral sucker length ratio, egg:body length ratio, and distribution of vitellaria. As in prior phylogenetic analysis of CO1 sequences, both D. ardeae and D. lunaschiae n. sp. were not associated with Diplostomum. In more character-rich analyses of nuclear rDNA and of mitochondrial genomes, D. ardeae was an early divergent member of clades of species of Diplostomum. Consequently, we continue to consider D. ardeae and D. lunaschiae n. sp. members of Diplostomum, in contrast to recent suggestions that these species may belong to a different genus.Facultad de Ciencias Naturales y Muse

System Dynamics to Model the Unintended Consequences of Denying Payment for Venous Thromboembolism after Total Knee Arthroplasty

Background: The Hospital Acquired Condition Strategy (HACS) denies payment for venous thromboembolism (VTE) after total knee arthroplasty (TKA). The intention is to reduce complications and associated costs, while improving the quality of care by mandating VTE prophylaxis. We applied a system dynamics model to estimate the impact of HACS on VTE rates, and potential unintended consequences such as increased rates of bleeding and infection and decreased access for patients who might benefit from TKA. Methods and Findings: The system dynamics model uses a series of patient stocks including the number needing TKA, deemed ineligible, receiving TKA, and harmed due to surgical complication. The flow of patients between stocks is determined by a series of causal elements such as rates of exclusion, surgery and complications. The number of patients harmed due to VTE, bleeding or exclusion were modeled by year by comparing patient stocks that results in scenarios with and without HACS. The percentage of TKA patients experiencing VTE decreased approximately 3-fold with HACS. This decrease in VTE was offset by an increased rate of bleeding and infection. Moreover, results from the model suggest HACS could exclude 1.5% or half a million patients who might benefit from knee replacement through 2020. Conclusion: System dynamics modeling indicates HACS will have the intended consequence of reducing VTE rates. However, an unintended consequence of the policy might be increased potential harm resulting from over administration of prophylaxis, as well as exclusion of a large population of patients who might benefit from TKA