421 research outputs found

    Sea lice exposure to non-lethal levels of emamectin benzoate after treatments: a potential risk factor for drug resistance

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    The avermectin derivative emamectin benzoate (EMB) has been widely used by salmon industries around the world to control sea lice infestations. Resistance to this anti-parasitic drug is also commonly reported in these industries. The objective of this study was to quantify the number of sea lice potentially exposed to sub-lethal concentrations of EMB while fish clear the drug after treatments. We assessed juvenile sea lice abundance after 38 EMB treatments on six Atlantic salmon farms, in a small archipelago in British Colombia, Canada, between 2007 and 2018. We fitted a standard EMB pharmacokinetic curve to determine the time when fish treated with this product would have EMB tissue concentrations below the recommended target therapeutic level. During the study, we estimated that for each sea lice treatment there was, on average, an abundance of 0.12 juvenile sea lice per fish during the time period when the concentrations of EMB would have been lower than 60ppb, the recommended therapeutic treatment level for sea lice. The findings from this study on metaphylactic anti-parasitic treatments identify a potential driver for drug resistance in sea lice that should be further explored

    Sea lice exposure to non-lethal levels of emamectin benzoate after treatments: a potential risk factor for drug resistance

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    The avermectin derivative emamectin benzoate (EMB) has been widely used by salmon industries around the world to control sea lice infestations. Resistance to this anti-parasitic drug is also commonly reported in these industries. The objective of this study was to quantify the number of sea lice potentially exposed to sub-lethal concentrations of EMB while fish clear the drug after treatments. We assessed juvenile sea lice abundance after 38 EMB treatments on six Atlantic salmon farms, in a small archipelago in British Colombia, Canada, between 2007 and 2018. We fitted a standard EMB pharmacokinetic curve to determine the time when fish treated with this product would have EMB tissue concentrations below the recommended target therapeutic level. During the study, we estimated that for each sea lice treatment there was, on average, an abundance of 0.12 juvenile sea lice per fish during the time period when the concentrations of EMB would have been lower than 60ppb, the recommended therapeutic treatment level for sea lice. The findings from this study on metaphylactic anti-parasitic treatments identify a potential driver for drug resistance in sea lice that should be further explored

    Risk Characterization For Introduction And Spread Of Multinucleate Sphere X (Msx) In Prince Edward Island, Canada

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    Multinucleate Sphere X (MSX) is an important pathogen of the eastern oyster (Crassostrea virginica) on the east coast of North America. This parasite is currently not present in Prince Edward Island (PEI), but there are concerns that it will spread from Cape Breton, Nova Scotia, where it was recently identified. Introduction of MSX to PEI would cause direct losses to the shellfish industry and it would have long-term implications for exports of oysters. The main goal of this study was to assess the risk of introduction and dissemination of MSX, as estimated by the number of movements of commercial oysters from three data sources. The in-degree (incoming) and out-degree (outgoing) of the contact network among bays, estuaries, and rivers were used to quantify the risks. For a single location on PEI, identification of up to 55 incoming and up to 26 outgoing movements to and from different locations within PEI were recorded. This suggests that if MSX was introduced it could be disseminated quickly. Movements of shellfish (oysters and mussels) from New Brunswick and Nova Scotia, which pose additional risks of pathogen introduction to PEI, were also identified. Two locations (New London Bay and the East-North-West River complex) were consistently ranked in the top quartile of incoming movements by the three data sources. In addition, two other locations (Bideford Area and Conway Narrows) were classified in the same quartile by only two of the data sources, suggesting that these four areas can be considered at high risk for pathogen introduction. Similarly, two locations were classified in the top quartile of outgoing movements (East-North-West River complex and Orwell Area) by the three data sources, whereas Bideford Area and Foxley River were only identified by two of the three data sources in the same quartile. These results indicate not only risk areas for pathogen introduction or dissemination, but also those areas having both high risk of introduction and high risk of dissemination (e.g., East-North-West River complex). Results of this study illustrate the potential consequences of MSX should Haplosporidium nelsoni reach PEI. Findings also highlight the need for the development of a system that captures all shellfish movements, which will be essential to mounting an effective response to pathogen introduction and mitigation of disease dissemination

    A record of the Surinam cockroach in Vancouver

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    Holding solution pH and composition consistently improve vase life of rose, lily and gerbera

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    We assessed the influence of postharvest pulsing solutions pH and composition on cut flower quality of rose (Rosa hybrida cvs. Avalanche and Black Magic), gerbera (Gerbera jamesonii cv. Beaudine) and lily (Lilium × elegans cv. Fangio) under room (20±2 °C) and cold storage (4±1 °C) conditions. Cut flowers were placed in different acidic (pH, 3.5 - 4) or basic (pH, 7.0 - 7.5) preservative solutions containing water, sugar 5% (flower food), 100 mg/L silver nitrate (AgNO3 act as a bactericide), or a commercial product (2% sugar + bactericide and fungicide). Acidic solutions had higher or similar (never lower) vase life at both room and cold storage conditions and across species. In addition, vase life was 3-4 times longer in cold storage when compared to room conditions. Leaf chlorophyll concentrations for rose and lily were inconsistent or not significant across the species at both conditions (room and cold storage). The commercial preservative solution consistently and significantly had higher vase life than water for all tested cut flower species and under both room and cold storage environments. AgNO3 ranked second in terms of vase life enhancement. Overall, the use of only flower food (sugar) or bactericide (AgNO3) had a positive impact on vase life but only the combined use of a preservative substance (specifically at pH, 3.5 - 4.0) consistently guaranteed a high cut flower quality across flower species

    McGill wetland model: evaluation of a peatland carbon simulator developed for global assessments

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    We developed the McGill Wetland Model (MWM) based on the general structure of the Peatland Carbon Simulator (PCARS) and the Canadian Terrestrial Ecosystem Model. Three major changes were made to PCARS: (1) the light use efficiency model of photosynthesis was replaced with a biogeochemical description of photosynthesis; (2) the description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and (3) the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition model divided into an oxic and anoxic zones by an effective water table, and a one-year residence time litter pool. MWM was then evaluated by comparing its output to the estimates of net ecosystem production (NEP), gross primary production (GPP) and ecosystem respiration (ER) from 8 years of continuous measurements at the Mer Bleue peatland, a raised ombrotrophic bog located in southern Ontario, Canada (index of agreement [dimensionless]: NEP = 0.80, GPP = 0.97, ER = 0.97; systematic RMSE [g C m<sup>−2</sup> d<sup>−1</sup>]: NEP = 0.12, GPP = 0.07, ER = 0.14; unsystematic RMSE: NEP = 0.15, GPP = 0.27, ER = 0.23). Simulated moss NPP approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated. Sensitivity analysis revealed that the model output did not change greatly due to variations in water table because of offsetting responses in production and respiration, but that even a modest temperature increase could lead to converting the bog from a sink to a source of CO<sub>2</sub>. General weaknesses and further developments of MWM are discussed

    McGill Wetland Model: evaluation of a peatland carbon simulator developed for global assessments

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    International audienceWe developed the McGill Wetland Model (MWM) based on the general structure of the Peatland Carbon Simulator (PCARS) and the Canadian Terrestrial Ecosystem Model. Three major changes were made to PCARS: 1. the light use efficiency model of photosynthesis was replaced with a biogeochemical description of photosynthesis; 2. the description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and 3. the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition model divided into an oxic and anoxic zones by an effective water table, and a one-year residence time litter pool. MWM was then evaluated by comparing its output to the estimates of net ecosystem production (NEP), gross primary production (GPP) and ecosystem respiration (ER) from 8 years of continuous measurements at the Mer Bleue peatland, a raised ombrotrophic bog located in southern Ontario, Canada (index of agreement [dimensionless]: NEP=0.80, GPP=0.97, ER=0.97; systematic RMSE [g C m?2 d?1]: NEP=0.12, GPP=0.07, ER=0.14; unsystematic RMSE [g C m?2 d?1]: NEP=0.15, GPP=0.27, ER=0.23). Simulated moss NPP approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated. Sensitivity analysis revealed that the model output did not change greatly due to variations in water table because of offsetting responses in production and respiration, but that even modest temperature increases could lead to converting the bog from a sink to a source of CO2. General weaknesses and further developments of MWM are discussed

    Original observations of Desmozoon lepeophtherii, a microsporidian hyperparasite infecting the salmon louse Lepeophtheirus salmonis, and its subsequent detection by other researchers

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    A microsporidian hyperparasite, Desmozoon lepeophtherii, of the parasitic copepod Lepeophtheirus salmonis (salmon louse), infecting farmed Atlantic salmon (Salmo salar), was first discovered in the west of Scotland in 2000. Heavily infected salmon lice are easily recognised as they have large opaque inclusions distributed throughout the body. The prevalence of salmon lice with visible signs of microsporidiosis can be up to 10% of the population from certain farm sites. The microsporidian was also isolated from the host Atlantic salmon suggesting it may have a two host life cycle. The authors believe that the infection in immunocompetent salmon may be latent, becoming acute during periods of infection with another pathogen or during sexual maturation. Since its first discovery in Scotland, Desmozoon lepeophtherii has been subsequently reported from Norway, and more recently from the Pacific coast of North America

    MEDICAL ACT IN THE CRIME OF TORTURE

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    A presente pesquisa verificou se a legislação surgida após a Segunda Guerra\ud Mundial foi apta a inibir o comportamento maleficente de médicos no auxílio em\ud especializar, dissimular e acobertar a tortura. Foi demonstrado o envolvimento\ud médico com experimentos em seres humanos durante a Segunda Guerra Mundial\ud e corroborou-se que a maleficência médica ainda é usada nos dias de hoje na\ud sociedade contemporânea, permitindo aos profissionais de saúde, desde o período da\ud Guerra Fria, o envolvimento com a tortura e a consequente violação dos princípios\ud da Bioética, especialmente, na conjuntura atualíssima da guerra norte-americana\ud contra o terrorismo. Ao final foram propostas soluções, tendo em vista as noções de\ud Bioética, as normas de Direito Internacional e os Direitos HumanosThe present research verified if legislation created after World War II was able to\ud inhibit maleficent behavior from medical doctors in the improvement and cover-up\ud of torture. It was demonstrated the medical involvement in experiments with human\ud beings during World War II and it was confirmed that medical maleficence was and\ud still is part of our reality, allowing doctors to involve with torture since the Cold War\ud until current days, especially in the United States’ war on terrorism, violating the\ud basic principles of Bioethics. In the end the objective was to propose solutions, in\ud light of notions of Bioethics, rules of International Law and Human Right
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