Zoonotic pathogens shared with wild or domesticated animals are the cause of more than 60% of human infectious diseases. These pathogens are responsible for millions of deaths annually and have resulted in costs of over a hundred billion U.S. dollars in the past three decades. Investigating different aspects of zoonotic pathogens can help inform policy decisions on public health, agriculture, and conservation of biodiversity. Because pathogens play essential roles in natural communities, studying the variables that influence pathogen richness is important in determining the biological principles governing biodiversity. Gaining a better understanding of the factors that influence these pathogens can allow for the development of effective and targeted action plans to deal with zoonotic disease outbreaks. The aims of this work were twofold: (1) to review the current literature and identify statistically significant predictors of pathogen richness, and (2) to analyze responses by public health agencies to recent zoonotic outbreaks. This work also discussed current gaps in the literature and suggested future areas of proposed funding and research.

Tableau d’honneur de la Faculté des études supérieures et postdoctorales, 2010-2011 / En raison de leur mode de vie et de leurs habitudes alimentaires, les Inuit sont probablement parmi les populations les plus exposées aux risques infectieux associés à la faune et à l'environnement. L'objectif principal de cette étude consistait à déterminer la séroprévalence de huit infections zoonotiques parmi la population du Nunavik. Les informations ont été recueillies à l'automne 2004 dans le cadre de l'Enquête sur la santé des Inuit du Nunavik ± Qanuippitaa ¿. Des prélèvements sanguins (n=917) ont été réalisés et analysés afin de vérifier la présence d'anticorps contre les micro-organismes à l'étude, soit Trichinella sp., Toxoplasma gondii, Toxocara canis, Echinococcus granulosus, Brucella sp., Coxiella burnetii, Leptospira sp. et Francisella tularensis. La présence des anticorps IgG a été détectée à l'aide de méthodes immunoenzymatiques (ELISA), à l'exception de F. tularensis, pour lequel un test d'agglutination en tube à été effectué. Des informations sociodémographiques ainsi que sur la pratique d'activités traditionnelles, l'environnement domestique et la nutrition ont été colligées par questionnaires et analysées à l'aide du test de khi carré dans le but de vérifier leur association avec les sérologies positives. Nos résultats montrent que 59,8% de la population inuite a été exposée à T. gondii, 3,9% à T. canis et 8,3% à E. granulosus. Pour les infections bactériennes, la séroprévalence était estimée à 5,9% pour Leptospira sp. et 18,9% pour F. tularensis. En contrepartie, les taux pour Trichinella sp., Brucella sp. et C. burnetii étaient inférieurs ou équivalents à 1,0% (n < 5). De manière générale, la séropositivité tend à augmenter avec l'âge. Les analyses multivariées révèlent que la séroprévalence était associée avec : l'âge et la résidence dans la région de l'Ungava pour F. tularensis; l'âge et la résidence dans la région de l'Hudson pour T. canis; le genre (femme), la scolarité et le nettoyage fréquent du réservoir d'eau domestique pour E. granulosus; l'âge, le genre (femme), la scolarité, l'exposition à de l'eau potable considérée ± plus à risque ¿, le nettoyage fréquent du réservoir d'eau domestique ainsi que la consommation de viande de phoque et de gibier à plumes pour T. gondii. Aucun facteur de risque précis n'était associé à la séropositivité pour Leptospira sp. À l'exception de T. gondii, aucune autre association n'a été décelée lorsque les données de séroprévalence étaient croisées avec les variables reliées à l'alimentation et à l'exposition environnementale. Cette étude est complétée par des entrevues qualitatives, réalisées à l'été 2006 afin de mieux comprendre les mécanismes impliqués dans l'exposition aux facteurs de risque et dans la prévention des infections zoonotiques au Nunavik.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Orientador: Marcelo Vasconcelos Meireles / Banca: Raphael Lúcio Andreatti Filho / Banca: Gisele Fabrino Machado / Resumo: Chlamydophila psittaci é uma bactéria que causa doença respiratória ou sistêmica em aves e em seres humanos. Há ainda, alguns relatos de infecção em aves por Chlamydophila abortus, que é um agente etiológico de problemas reprodutivos em mamíferos. Em vista do risco de transmissão para humanos a partir de aves assintomáticas o objetivo deste estudo foi detectar a presença de C. psittaci e C. abortus em amostras de fezes ou suabes cloacais de aves assintomáticas. Foram colhidas 403 amostras fecais ou suabes cloacais, provenientes de aves domésticas, selvagens ou exóticas, mantidas em cativeiro ou oriundas de apreensão. As amostras foram submetidas à PCR em tempo real para C. psittaci e C. abortus, para amplificação de fragmento parcial do gene da subunidade 16S do rRNA, utilizando o SsoFast™ EvaGreen® Supermix (Bio-Rad) e análise da curva de dissociação. Para determinação do genótipo de C. psittaci, foi utilizada a hemi- nested PCR específica para o gene OMP-A, realizada nas amostras positivas pela PCR em tempo real, seguida de sequenciamento dos fragmentos amplificados. A PCR em tempo real revelou positividade em 17 (4,21%) amostras. A hemi-nested foi positiva em 2 amostras positivas pela PCR em tempo real. O genótipo A de C. psittaci foi identificado pelo sequenciamento de uma amostra amplificada pela hemi-nested PCR / Abstract: Chlamydophila psittaci is a bacterium that causes respiratory or systemic disease in birds and humans. In birds there is also some reports of infection by Chlamydophila abortus that is responsible for abortions in mammals. Owing to the risk of transmission of Chlamydophila from asymptomatic birds to humans, the objective of this study was to detect the presence of C. psittaci and C. abortus in asymptomatic birds. Four hundred and three fecal samples or cloacal swabes were collected from domestic, wild or exotic birds kept in captivity or from apprehension. The 403 samples were examined by real time PCR specific for the 16S subunit of rRNA gene using SsoFastEvaGreen®Supermix™(Bio-Rad) and melting curve analysis. Hemi- nested PCR specific for the OMP-A gene, accomplished in real-time PCR positive samples, followed by sequencing of the amplified fragments were used to determine the genotype of C. psittaci. Real-time PCR was positive in 17 (4.21%) samples. Hemi-nested PCR revealed positivity in two samples previously positive by real-time PCR. Sequencing of the fragment amplified by hemi-nested PCR allowed for the identification of genotype A of C. psittaci in one sample / Mestre

This research focuses on occupational exposures associated with Methicillin-resistant Staphylococcus aureus (MRSA) in modern pork production facilities. This dissertation is composed of three related parts. In Chapter II, "Methicillin-resistant Staphylococcus aureus in pork production shower facilities" we documented the presence of MRSA in shower facilities of conventional swine production systems where pigs were colonized with MRSA. We tested farms involved in different production phases (sow, nursery, and finisher) and geographical locations. In the two swine production systems studied, 3% and 26% of shower samples were positive for MRSA. Overall, the prevalence in showers was 19%. In Chapter III, "Methicillin-resistant Staphylococcus aureus in pork production shower facilities: Adapting interventions from athletic facilities," we searched the literature for interventions designed to decrease MRSA infections in athletes. We then evaluated these interventions for adaptability to the pork production environment, and composed swine-specific guidelines for MRSA prevention. We implemented our intervention in a pilot study to reduce MRSA in showers and locker rooms and results were mixed. We recommend repeating this study with a larger sample, and better intervention management and oversight. In Chapter IV, "Methicillin-resistant Staphylococcus aureus infection in pork production workers," we sought to determine if pork producers report veterinarian-diagnosed antibiotic-resistant skin infections in pigs, and physician-diagnosed antibiotic-resistant skin infections in workers (including MRSA). We then examined potential risk factors for infection associated with biosecurity, including shower and laundry procedures, farm-specific clothing use (clothing worn only while working on the farm), and personal hygiene. No significant risk factors were identified for either skin infections in pigs or skin infections in workers. These studies provide evidence that MRSA can be found in pork production shower facilities, and that occupational exposures occur due to components of the biosecurity protocol. We designed and implemented an intervention to decrease the level of MRSA in showers. Our pilot intervention suggested that the impact of showers as environmental reservoirs can be reduced. We also reported the first prevalence estimate of MRSA infection in pork production workers in the United States. Livestock-associated MRSA remains an emerging issue and requires further study to determine the true occupational and public health risks.

In this dissertation I explore the application of two novel modeling techniques for improving risk analysis of vector-borne disease and discuss their potential use in integrating environmental risk assessment that guides environmental and public health decisions. Techniques for analyzing risk have been considered inadequate due to a lack of understanding of the problem and an appropriate analytic-deliberative process clarifying the meaning of analytic findings and uncertainty (National Research Council (NRC), 1996; Peterman and Anderson, 1999). Thus, new integrative risk analysis tools are needed that are responsive to more complex environmental problems. In this work, I develop a qualitative community model that combines a conventional biomathematical model of vector-borne disease transmission with recent developments in community modeling. My procedure predicts the change in risk of vector-borne disease from press perturbations, a disturbance that results in a permanent change in a growth parameter. I also use a Relational Bayesian Modeling technique to exploit existing data to determine plausible mechanisms and geospatial and temporal patterns of disease spread. I apply these tools to Lyme disease and West Nile Encephalitis as examples of two different vector-borne diseases associated with complex ecological communities. Both the qualitative modeling and Bayesian methods provide an integrated risk analysis framework that identifies relationships important in the system and thus, guide the application of quantitative models or provide sufficient information for management decisions. / Graduation date: 2003

Thèse d'exercice : Pharmacie : Nantes : 2003. / Thèse : 2003NANT038P. Bibliogr. f. 179-184 [68 réf.].

Reproduction de : Thèse d'exercice : Pharmacie : Nantes : 2009. / Bibliogr.

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