33 resultados para Simulium pertinax
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The aim of this work was to determine the distribution and abundance the species of Simulium: in 5 streams of the north coastal region of the state of São Paulo. Simulium larval and water samples were collected every 2 weeks in summer and winter, 2001. The larval were collected on artificial substrates (triplicate) preserved in alcohol (70%) and after analyzed quantitative and qualitative. From the streams the values of temperature, dissolved oxygen, conductivity, pH and stream discharge were measured. The contents of total nitrogen and dissolved nitrogen, ammoniacal nitrogen, nitrate, nitrite, orthophosphate, dissolved phosphorus and total phosphorus were determined in the laboratory. Water quality has great influence in the distribution and abundance of the species. S. pertinax was more abundant in streams without or with low levels of pollution, S. inaequale in streams more polluted and S. incrustatum in intermediary levels of pollution. S. pertinax was the species more abundant with 57.5% of presence in the samples, the second more abundant was S. inaequale with 42.1% of presence and S. incrustatum was rare with 0.4% of presence. The larval abundance was lower in the polluted environment. © 2012 by Unisinos.
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Spatio-temporal data on cytotaxonomic identifications of larvae of different members of the Simulium damnosum complex collected from rivers in southern Ghana and south-western Togo from 1975 until 1997 were analysed. When the data were combined, the percentages of savannah blackflies (S. damnosum sensu stricto and S. sirbanum) in the samples were shown to have been progressively increasing since 1975. The increases were statistically significant (P < 0·001), but the rates of increase were not linear. Further analyses were conducted according to the collection seasons and locations of the samples, to account for possible biases such as savannah flies occurring further south in the dry season or a preponderance of later samples from northern rivers having more savannah flies. These analyses showed that the increasing trend was statistically significant (P< 0·0001) only during the periods April to June and October to December. The presence of adult savannah flies carrying infective larvae (L3) indistinguishable from those of Onchocerca volvulus in the study zone was confirmed by examinations of captured flies. The percentages of savannah flies amongst the human-biting populations and the percentages with L3s in the head were higher during dry seasons than wet seasons and the savannah species were found furthest south (5 °25′N) in the dry season. Comparisons of satellite images taken in 1973 and 1990 over a study area in south-western Ghana encompassing stretches of the Tano and Bia rivers demonstrated that there have been substantial increases in urban and savannah areas, at the expense of forest. This was so not only for the whole images but also for subsamples of the images taken at 1, 2, 4, 8 and 16 km distant from sites alongside the River Tano. At every distance from the river, the percentages of pixels classified as urban or savannah have increased in 1990 compared with 1973, while those classified as degraded or dense forest have decreased. The possibility that the proportionate increases in savannah forms of the vectors of onchocerciasis, and hence in the likelihood of the transmission of savannah strains of the disease in formerly forested areas, were related to the decreases in forest cover is discussed.
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Tesis (Maestría en Ciencias con Especialidad en Entomología Médica) U.A.N.L.
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Insect bite hypersensitivity (IBH) is an IgE-mediated seasonal dermatitis of the horses associated with bites of Simulium (black fly) and Culicoides (midge) species. Although cross-reactivity between Simulium and Culicoides salivary gland extracts has been demonstrated, the molecular nature of the allergens responsible for the observed cross-reactivity remains to be elucidated. In this report we demonstrate for the first time in veterinary medicine that a homologous allergen, present in the salivary glands of both insects, shows extended IgE cross-reactivity in vitro and in vivo. The cDNA sequences coding for both antigen 5 like allergens termed Sim v 1 and Cul n 1 were amplified by PCR, subcloned in high level expression vectors, and produced as [His](6)-tagged proteins in Escherichia coli. The highly pure recombinant proteins were used to investigate the prevalence of sensitization in IBH-affected horses by ELISA and their cross-reactive nature by Western blot analyses, inhibition ELISA and intradermal skin tests (IDT). The prevalence of sensitization to Sim v 1 and Cul n 1 among 48 IBH-affected horses was 37% and 35%, respectively. In contrast, serum IgE levels to both allergens in 24 unaffected horses did not show any value above background. Both proteins strongly bound serum IgE from IBH-affected horses in Western blot analyses, demonstrating the allergenic nature of the recombinant proteins. Extended inhibition ELISA experiments clearly showed that Sim v 1 in fluid phase is able to strongly inhibit binding of serum IgE to solid phase coated Cul n 1 in a concentration dependent manner and vice versa. This crucial experiment shows that the allergens share common IgE-binding epitopes. IDT with Sim v 1 and Cul n 1 showed clear immediate and late phase reactions to the allergen challenges IBH-affected horses, whereas unaffected control horses do not develop relevant immediate hypersensitivity reactions. In some horses, however, mild late phase reactions were observed 4h post-challenge, a phenomenon reported to occur also in challenge experiments with Simulium and Culicoides crude extracts probably related to lipopolysaccaride contaminations which are also present in E. coli-expressed recombinant proteins. In conclusion our data demonstrate that IgE-mediated cross-reactivity to homologous allergens, a well-known clinically relevant phenomenon in human allergy, also occurs in veterinary allergy.
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Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis of horses caused by bites of insects such as Culicoides or Simulium spp. The aim of the present study was to compare the IgE-binding pattern of sera of IBH-affected horses to Culicoides nubeculosus and Simulium vittatum salivary gland extracts (SGE). Individual IgE responses to proteins of S. vittatum and C. nubeculosus SGEs were evaluated in 15 IBH-affected and three healthy horses on immunoblots. Fourteen out of the 15 IBH-affected but none of the healthy horses showed individual IgE binding patterns to seven and six main protein bands in C. nubeculosus and S. vittatum SGE, respectively. These 14 sera showed IgE-binding to proteins from SGE of both C. nubeculosus and S. vittatum, but they reacted with fewer protein bands derived from S. vittatum than from C. nubeculosus SGE. Sera showing IgE-binding to a 32 kDa band from C. nubeculosus always bound to a 32 kDa band from S. vittatum. Similarly, all sera binding to a 70 kDa band from C. nubeculosus reacted with a corresponding band in S. vittatum SGE. The 70 kDa bands from S. vittatum and C. nubeculosus were identified by mass spectrometry as heat shock protein-70-cognate-3.
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Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of Culicoides and sometimes Simulium spp. The aim of this investigation was to identify Simulium allergens associated with IBH. A phage surface display cDNA library expressing recombinant Simulium vittatum salivary gland proteins was screened using sera of IBH-affected horses sensitized to S. vittatum salivary gland proteins as shown in immunoblot, resulting in the identification of seven cDNAs encoding IgE-binding proteins. The deduced amino acid sequences of these proteins showed sequence similarities to antigen 5 like protein (Sim v 1), to a serine protease inhibitor (Sim v 2), to two alpha-amylases (Sim v 3 and Sim v 4), and to three S. vittatum erythema proteins (SVEPs). The cDNA inserts were subcloned and expressed as [His](6)-tagged protein in Escherichia coli and purified using Ni(2+)-chelate affinity chromatography. Mice were immunised with the seven recombinant proteins and the antibodies tested against the recombinant proteins and salivary gland extract (SGE) of S. vittatum and Culicoides nubeculosus in immunoblot analyses. r-Sim v 1 specific mouse Abs recognized a band of about 32 kDa in immunoblots of both S. vittatum and C. nubeculosus SGE, detectable also by serum IgE of IBH-affected horses. Preincubation of horse serum with r-Sim v 1 completely inhibited IgE binding to the 32 kDa band demonstrating the presence of cross-reactive antigen 5 like proteins in both SGE. Determination of IgE levels against the r-Sim v proteins and crude S. vittatum extract by ELISA in sera from 25 IBH-affected and 20 control horses showed that IBH-affected horses had significantly higher IgE levels than controls against r-Sim v 1, 2, 3, 4 and S. vittatum extract, whereas the r-SVEP showed only marginal IgE binding. Further analyses showed that 60% of IBH-affected horses reacted to r-Sim v 1, suggesting that this could be a major allergen for IBH. Forty to twenty percent of the IBH-affected horses reacted with r-Sim v 2, 3 or 4. Combination of the results obtained with the 4 r-Sim v proteins showed that 92% of the IBH-affected but only 15% of the healthy horses had IgE levels against one or more of the 4 r-Sim v proteins. Seventy percent of the healthy horses had detectable IgE against S. vittatum extract, indicating a low specificity of the detection system used. Optimization of the ELISA system will be required to determine reliable cut-off values for the IBH-related allergens. Their in vivo relevance needs to be carefully assessed.
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Mode of access: Internet.
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Abstract: I will focus on the Roman Empire during the final years of the 2nd century A.D., which are considered by Classical Historiography as critical. This epithet is based on the detection of estructural and circumstancial changes linked to state power’s concept. Emperor Pertinax’s murder in 193 can be understood as the trigger of the civil war extended up to the year 197. During those years the tutelary of state power was jeopardized, when four Emperors were crowned at the same time. By the time this struggle ended, Lucius Septimius Severus was recognized as the victorious general and the first of his name in the new dynastic line. Considering these facts, it is the purpose of my work to analize the rising figure of Septimius Severus, from civil war’s clashing context through which the Emperial legitimacy had to be set.
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O objetivo desta Tese é realizar o levantamento taxonômico e avaliar a dinâmica populacional de Simuliidae em localidades sob influência do Aproveitamento Hidrelétrico de Peixe Angical, TO. Os simulídeos possuem abrangente distribuição geográfica, e os estágios imaturos utilizam ambientes lóticos como sítios de criação. Algumas espécies podem atuar como vetores de vírus, protozoários e helmintos, o que confere ao grupo importância médica e veterinária. O hábito hematofágico das fêmeas de simulídeos pode acarretar sérios prejuízos ao turismo; ocasiona baixa no rendimento escolar; e na agropecuária dificulta a execução do trabalho o que reduz a produtividade. Durante a construção de grandes empreendimentos ocorre em pouco tempo à introdução de contingente populacional com drástica transformação do meio. A intervenção do homem sobre os ecossistemas e o crescimento desordenado pode provocar desequilíbrio ecológico que propicia a proliferação de espécimes vetores com consequentes problemas médico sanitários. A maior parte dos trabalhos realizados com insetos vetores em áreas sob influência da construção de hidrelétricas se refere aos culicídeos. O estudo dos aspectos taxonômicos permitirá o levantamento da biodiversidade e o diferencial deste projeto está no estabelecimento da sazonalidade e dinâmica das populações de imaturos e adultos de simulídeos. As amostras foram obtidas em áreas de influência direta e indireta da UHE Peixe no rio Tocantins, em 12 pontos diferentes de coleta, nos municípios deJaú do Tocantins, Peixe, Palmeirópolis, Paranã e São Salvador do Tocantins. Foram realizadas bimestralmente de 2004 a 2007, um total de 24 campanhas para coleta em criadouros pré-selecionados, que acompanharam todas as fases de construção início das obras, formação do lago, funcionamento da Usina. OS dados abióticos foram aferidos, e os imaturos removidos do substrato manualmente por 10 minutos e posteriormente preparados para eclosão dos adultos. Parte do material foi identificado no Laboratório de Simulídeos e Oncocercose do Instituto Oswaldo Cruz, onde foram verificados novos registros específicos para a ocorrência de Simuliidae em Tocantins, além do assinalamento de espécies antropofílicas e/ou vetores de Onchocerca volvulus. Nas áreas usadas para a formação do lago houve desaparecimento de criadouros. O desmatamento ocorrido aliado ao vigor dos simulídeos que conseguem realizar voos de longas distâncias na procura de alimento ou locais adequados a oviposição devem ter contribuído para a dispersão de espécimes. Há relatos sobre a da ocorrência de oncocercose na área estudada, um foco foi demarcado na divisa de Goiás com Tocantins, municípios Paranã e Minaçu investigado a partir de um caso autóctone de oncocercose. Este estudo é relevante uma vez que o Brasil possui potencial hidroenergético e prevê a construção de inúmeras hidrelétricas nos próximos anos. É importante estudas as áreas impactadas, conhecer a sua biodiversidade e os aspectos bioecológicos de Simuliidae no país.
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The present study deals with the chemical, algal and faunal characteristics of the stream system at Horton Plains, the highest plains in Ceylon (altitude 2'225 m). The cultivation of seed potatoes and subsequent use of fertilizers have caused extensive silting and severe eutrophication of the stream systems. Since there are no indigenous fish, the trout Salmo gairdnerii has been introduced and it is the only fish found in these streams. The commonest fauna in the streams are crabs (Paratelphusa sp.), shrimps (Caridimr sp.), Simulium sp. and Chironomus sp. Their increase in number is probably correlated with increase in organic and detritus matter. The most important food items of the trout are the crabs living abundantly in the stream, insect larvae and terrestrial insects were also commonly found in the guts. Records of stocking and taking of trout in the Horton plains streams have shown that now less trout are taken relatively to the numbers stocked. This decrease may be possibly due to the eutrophication of the stream and also due to the possible use of pollutants in connection with the cultivation of seed potatoes.
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2003
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Summary
-Predatory functional responses play integral roles in predator–prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species.
-Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator–prey interactions and thus the predictive capability of the comparative functional response approach.
-We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses.
-Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator.
-Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator.
-This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies.