Assessment in Québec of a french ecopathologic tool designed to investigate postweaning digestive disorders in piglets

Cette étude avait pour objectif de déterminer l’applicabilité au Québec d’un outil écopathologique français d’investigation des troubles digestifs après le sevrage en élevage porcin intensif. Cet outil détermine le niveau des troubles cliniques et le niveau du risque circonstanciel associé à partir de 13 variables. Il a été appliqué dans 60 élevages québécois choisis au hasard. Pour chacun, la valeur des 13 variables a été mesurée, parfois avec difficulté et les niveaux des troubles et du risque déterminés. Cette présentation discute des problèmes pratiques et méthodologiques liés à l’utilisation de l’outil. 11 y a quatre niveaux de mesure tous analysés sur le même plan. De plus, l’outil s’applique de façon statique sur des phénomènes dynamiques. Enfin, la similitude entre l’élevage d’application et les élevages bretons qui ont servi à l’élaboration de l’outil n’a pas été rencontrée. Les distributions de 10 des 13 variables sont significativement différentes entre l’échantillon d’élevages québécois et l’échantillon d’élevages bretons. Comme cette simi litude est nécessaire pour appliquer l’outil, celui-ci n’est donc pas utilisable au Québec.This study was designed to assess whether an ecopathologic tool made for the investigation of postweaning digestive disorders in piglets could be used in Québec intensive herds. This French tool allows to determine from 13 variables evaluated on the farm the level of the clinical problems and the level of specific risk factors. The tool was applied in 60 pig randomly selected herds in Québec. For each farm, the 13 variables were measured and the clinical problems and risk levels were determined. Practical and methodolo gical problems are discussed. Some variables are difficult to measure. There are four units of observation all considered as only one. The tool is applied in a sta way upon dynamic processes. Moreover, the conditions for its use described by the designers were not met. The distributions of 10 out 13 variables from the Québec data set were significantly different from the French one from which the tool was developed. It was concluded that the echopathological tool cannot be used in Québec

Risk maps for range expansion of the Lyme disease vector, Ixodes scapularis, in Canada now and with climate change

<p>Abstract</p> <p>Background</p> <p>Lyme disease is the commonest vector-borne zoonosis in the temperate world, and an emerging infectious disease in Canada due to expansion of the geographic range of the tick vector <it>Ixodes scapularis</it>. Studies suggest that climate change will accelerate Lyme disease emergence by enhancing climatic suitability for <it>I. scapularis</it>. Risk maps will help to meet the public health challenge of Lyme disease by allowing targeting of surveillance and intervention activities.</p> <p>Results</p> <p>A risk map for possible Lyme endemicity was created using a simple risk algorithm for occurrence of <it>I. scapularis </it>populations. The algorithm was calculated for each census sub-division in central and eastern Canada from interpolated output of a temperature-driven simulation model of <it>I. scapularis </it>populations and an index of tick immigration. The latter was calculated from estimates of tick dispersion distances by migratory birds and recent knowledge of the current geographic range of endemic <it>I. scapularis </it>populations. The index of tick immigration closely predicted passive surveillance data on <it>I. scapularis </it>occurrence, and the risk algorithm was a significant predictor of the occurrence of <it>I. scapularis </it>populations in a prospective field study. Risk maps for <it>I. scapularis </it>occurrence in Canada under future projected climate (in the 2020s, 2050s and 2080s) were produced using temperature output from the Canadian Coupled Global Climate Model 2 with greenhouse gas emission scenario enforcing '<it>A2</it>' of the Intergovernmental Panel on Climate Change.</p> <p>Conclusion</p> <p>We have prepared risk maps for the occurrence of <it>I. scapularis </it>in eastern and central Canada under current and future projected climate. Validation of the risk maps provides some confidence that they provide a useful first step in predicting the occurrence of <it>I. scapularis </it>populations, and directing public health objectives in minimizing risk from Lyme disease. Further field studies are needed, however, to continue validation and refinement of the risk maps.</p

Evaluation de l'impact sur la qualité de l'eau du traitement de l'azote et du phosphore dans les effluents urbains

info:eu-repo/semantics/publishe

Modelling the dry and wet weather impact of urban areas: example across a gradient of demographic pressure

info:eu-repo/semantics/nonPublishe

Inorganic nitrogen dynamics in the River Seine downstream from Paris (France)

The River Seine, below Paris, receives the effluents from a large sewage treatment plant, increasing the ammonium concentration up to 6 mgN.1 - in late summer. Careful measurement of ammonium, nitrate and organic nitrogen during the downriver travel of the water masses over 100 km below the outfall, along with direct determination of nitrification and benthic fluxes, allowed to establish a budget of nitrogen transport and transformations in this reach of the river. Nitrification is shown to start after a distinct period of several days required for the growth of a significant nitrifying bacterial population. Denitrification is active in the upper layer of bottom sediments but absent from the water column. Comparison of our data with those published for the period 1973-1976 shows that the nitrate load carried by the river has increased not only because of higher runoff of agricultural nitrate in the upstream part of the watershed, but also as a result of the severe reduction in the rate of denitrification processes, owing to the restoration of better oxygen conditions. © 1992 Kluwer Academic Publishers.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Fate and Transport of Toxoplasma gondii Oocysts in Seasonally Snow Covered Watersheds: A Conceptual Framework from a Melting Snowpack to the Canadian Arctic Coasts

Toxoplasma gondii is a zoonotic protozoan that causes serious illness in humans and infects animals worldwide, including the Canadian Arctic. Indeed, high prevalence of infection amongst Inuit has been recorded, possibly due to consumption of raw infected seal meat. Here we explore the hypothesis that T. gondii oocysts contaminate the coastal marine environment via surface runoff from across the boreal watershed, particularly during the snowmelt period. We propose a conceptual framework of the different processes governing the fate and transport of T. gondii oocysts from the melting snowpack to the Canadian arctic coast via the freshwater runoff. This framework identifies the feasibility of a transmission pathway of oocysts from contaminated soil to the marine environment, but also the complexity and multiplicity of mechanisms involved. In addition, the framework identifies knowledge gaps for guiding future studies on T. gondii oocysts. Furthermore, this work could be used as a tool to investigate the possible estuarine contamination by other faeces-borne pathogens transported via the spring freshet in seasonally snow covered watersheds

Modelling oxygen deficits in the Seine River downstream of combined sewer overflows

The impact of combined sewer overflows on the Seine River was studied for the scientific interest of understanding highly transient situations and for the management challenges they represent. Measurements were made in the Seine River downstream of a combined sewer overflow (CSO) to identify the relevant variables describing the evolution of water quality. The combined effects of various processes influencing oxygen depletion after a rain event were analysed given all the available data. A complete oxygen balance was established to rank the relative importance of the processes. The model PImage SImage used for these tasks was designed in the framework of a long term multidisciplinary research program devoted to the Seine River catchment. A comparison of the model we used with existing models was done. The conceptual model was especially adapted for this highly impacted urban ecosystem. Apart from usual processes considered in river ecological modelling, sedimentation and erosion of particles, a biologically active and mobile benthic boundary layer (Image ), exchange of particles and diffusion of solutes between this Image and the water column, detailed descriptions of algal and bacteria physiology were taken into account. To explain the oxygen depletion in the river, the more relevant variables appear to be the quantity of bacteria brought by the overflow and the biodegradable dissolved organic carbon concentrations. Specific contribution to the evolution of water quality of the river of particles that are sedimenting, was investigated, including the micro organisms brought by the overflows. For this highly eutrophicated river, the influence of the reduction of photosynthesis activity due to cloud cover was quantified. The influence of the toxicity of the CSO on the phytoplanktonic photosynthesis was studied experimentally and taken into account in the model. The resulting effect is a delayed oxygen depletion inside the plume of polluted water.info:eu-repo/semantics/publishe