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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Invasion d’Aedes albopictus dans les milieux forestiers tropicaux et potentiel pour l’émergence de virus zoonotiques au Brésil / Invasion of Aedes albopictus in tropical forest and potential for the emergence of zoonotic viruses in Brazil

Pereira Dos Santos, Taissa 19 March 2019 (has links)
Les zoonoses émergentes sont en augmentation au cours des dernières décennies. Ainsi, il y est urgent de comprendre les mécanismes de cette émergence, en particulier d’étudier les facteurs écologiques sous-jacents qui déterminent les transferts de ces maladies de l’animal à l’homme.Originaire d’Asie, le moustique tigre Aedes albopictus est arrivé au Brésil dans les années 80 et s’est établi dans 60% des villes brésiliennes. Les forêts brésiliennes sont considérées comme un point chaud de la biodiversité mondiale, abritant des centaines d'arbovirus zoonotiques. Ces forêts que, par fois, cercles des grandes agglomérations urbaines, souffrent de la transformation du paysage réalisé par l’homme, un terreau idéal pour l'apparition de zoonoses. Cette espèce représente une préoccupation majeure pour la transmission d’arbovirus épidémiques (Dengue, Chikungunya, Zika) mais également une menace potentielle pour l’émergence de maladies zoonotiques en raison de sa présence dans les interfaces ville / forêt, de son comportement alimentaire opportuniste et de sa compétence vectorielle pour nombreux virus. Ainsi, Ae. albopictus pourrait potentiellement jouer le rôle de vecteur pont pour le transfert en milieu urbain de arbovirus zoonotiques qui circulent dans les forêts brésiliennes. Dans cette étude, nous évaluons le potentiel de cette espèce à servir de vecteur de pont entre la faune et l'homme. Pour cette proposition (i) Nous avons effectué une recherche et une analyse bibliographiques portant sur trois éléments clés permettant d’évaluer la capacité de ce moustique à assurer le transfert interspécifique des arbovirus dans les zones sylvatiques : 1) la capacité à exploiter les sites de reproduction larvaire naturels, 2) le comportement alimentaire et 3) la compétence vectorielle pour les dif férentes arbovirus. (ii) Nous avons étudié sur le terrain la colonisation, la dispersion, le comportement trophic et l'impact sur la biodiversité d'Ae. albopictus dans l'interface ville / forêt au Brésil. Ce travail de terrain a été réalisé à partir de dix écosystèmes de fragments de forêts dans trois Biomes au Brésil: 1) Biome Amazonia dans la réserve forestière d'Adolpho Ducke à Manaus; 2) Biome Mata Atlantica dans la réserve forestière de Pedra Branca à Rio de Janeiro, dans les fragments de forêt urbaine à Salvador, Serra, Belo Horizonte et dans les fragments de forêt rurale à Domingos Martins, Simonésia, Casimiro de Abreu, Marica-RJ; Biome Cerrado dans la forêt de Morro dos Macacos à Goiania. Dans cette thèse nous avons confirmé qu’Ae. albopictus a la capacité de coloniser des sites de reproduction naturels avec un comportement alimentaire opportuniste et une claire préférence pour les sources de sang humain, suivi par d'autres mammifères et oiseaux. Nous observons que le processus de colonisation et de dispersion est limité à la bordure de la forêt avec un impact sur la composition des espèces dans ces environnements. Nous avons observé également que ce moustique est capable de transmettre 13 arbovirus dans notre recherche bibliografic, mais aucun arbovirus n’a été détecté chez des moustiques prélevés lors du travail de terrain. Globalement, nos résultats confirment et estiment le rôle potentiel d’Ae. albopictus comme vecteur pont des maladies zoonotiques aux interfaces forêt / ville au Brésil. Ces travaux ouvrent un domaine de recherche dans lequel de nouvelles investigations pourraient évaluer le risque potentiel de propagation des maladies zoonotiques des zones forestières aux zones urbaines, dans le but de limiter les futures émergences virales. / Zoonotic emerging diseases are increasing during the last decades. There is an urgent need to understand the mechanisms of this emergence, in particular to study the underlying ecological factors determining spill-over events, the transfer from animals to humans. Being native from Asia, the tiger mosquito Aedes albopictus arrived to Brazil in the 80’s being nowadays established in 60% of brazilian cities. Brazilian forests are considered a hotspot of wildlife biodiversity, harbouring hundreds of zoonotic arboviruses, suffering human landscape transformation and surrounding large urban cities, an optimal breeding ground for the emergence of zoonotic diseases. This species represents a major concern for the transmission of epidemic arboviruses (dengue, chikungunya, Zika) but also a potential threat for the emergence of zoonotic diseases due to its presence in urban/forest interfaces, its opportunistic feeding behavior and its vector competence to transmit numerous viruses. Thus, Ae. albopictus might potentially participate as a bridge vector for the transfer to urban environments of zoonotic arboviruses that are circulating on Brazilian forests. In this study we evaluate the potential of this species to act as a bridge vector between wildlife and humans. For this propose (i) we performed a bibliographic research and analysis focusing on three key components for assessing the ability of a mosquito to ensure interspecies transfer of arboviruses in sylvatic areas: 1) the capacity to exploit natural larval breeding sites, 2) blood-feeding behaviour and 3) the vector competence for arboviruses. (ii) We investigated from fieldwork the colonization, dispersion, host feeding and potential impact of biodiversity patterns of Ae. albopictus in the urban/forest interface in Brasil. This field work was realized from ten forest-fragments ecosystems in tree Brazilians Biome: Biome Amazonia in Adolpho Ducke forest reserve-Manaus; Biome Mata Atlantica in Pedra Branca forest reserve- Rio de Janeiro, in the urban forest fragment Salvador, Serra, Belo Horizonte and in the rural forest fragment Domingos Martins, Simonésia, Casimiro de Abreu, Marica-RJ; Biome Cerrado in Morro dos Macacos forest – Goiania. This work confirmed that Ae. albopictus has the capacity to colonize natural breeding sites with the opportunistic feeding behavior with a preference for human blood sources, followed by other mammals and birds. We observe that the colonization and dispersion process is limited to the edge forest with an impact in species composition in this environments. We observed that this mosquitos is vector competence for 13 arbovirus from bibliographic recherché, but no arbovirus was detected from fildework collected mosquitos. Globally our results confirm and estimates the potential role of Ae. albopictus to act as a bridge vector of zoonotic diseases at the forest/urban interfaces in Brazil. This work opens a research area in which further investigations may assess the potential spill-over risk of zoonotic disease from forested to urban areas with the aim to mitigate potential future viral emergences.
2

The disease-scape of the new millennium : a review of global health advocacy and its application

Mableson, Hayley Elizabeth January 2014 (has links)
The global disease scape is constantly shifting, influenced by demographic transitions, altering the balance of the burden of infectious and non‐communicable diseases. The epidemiological transitions can be divided into three stages: the first, an increase in infectious disease burden as populations settled, then grew into towns and cities providing conditions for infectious agents to maintain spread; the second transition follows industrialisation, changes in lifestyle, diet and improved sanitation whereby infectious diseases are reduced and non‐communicable disease (NCD) prevalence increases; the third transition describes the re‐emergence of infectious diseases as the AIDS epidemic and other emerging and re‐emerging disease outbreaks lead to an increasing burden of infectious diseases, particularly in developing countries. Analysis of the disease‐scape has been carried out using WHO Global Burden of Disease data and correlation to demographic factors calculated using World Bank Development Indicators. The balance of chronic NCDs and infectious diseases can be represented numerically as the unit rate of infectious to non‐communicable diseases. The rate, which indicates at which end the continuum lies can then be correlated to these demographic development indicators to assess the factors which are influential to the continuum. As the balance of infectious and non‐communicable diseases around the world alters, the focus of the advocacy at the global health level has been examined to assess if the trends follow that of the shifting continuum. This has been carried out through an assessment of the WHO World Health Assembly (WHA) resolutions adopted annually between 1948 and 2013 on the subject of infectious and/or non-communicable diseases. The principle of International health stemmed from the need to contain the international spread of communicable diseases, so it is not surprising that in the first decade of the WHO, 88% of the resolutions adopted for infectious and non‐communicable disease were adopted for infectious diseases. In the latest ten years of the WHO, 72% of the Assembly resolutions for infectious and non‐communicable diseases were focused on infectious diseases; this indicates that while there has been a shift in the balance, the adopted resolutions still focus heavily on infectious diseases. An example of how advocacy can elevate diseases to a higher position on the global health agenda is that of the Neglected Tropical Diseases. Following the Millennium Development Goals, this group of seventeen diseases has been highlighted as being “neglected” in terms of funding, research and political will. A review of the campaign to highlight this shows how global health advocacy can elevate diseases to a prominent position on the global health agenda. With this in mind, the advocacy for a sub‐group of Neglected Zoonotic Diseases has been examined at the WHA level. The results highlight the sporadic nature of support to control these diseases, and that activism for control of some of the major zoonotic diseases remains lacking. Rabies is explored as an example of a disease for which there are recommendations and support at the global level for the control and elimination of the disease, but for which barriers to control exist locally in endemic countries. The advocacy for diseases at the global health level has the possibility to impact the priorities of health care within individual nations. However the advocacy at this level may take time to reflect the changes within the disease‐scape. The impact of such advocacy is also limited by local political will, availability of resources and local cultural implications. Therefore there is a need to ensure that efforts to control diseases are tailored to specific populations and that resources are made available to support the advocacy.
3

Élaboration d'une méthode semi-automatique pour l'identification et le traitement des signaux d'émergence pour la veille internationale sur les maladies animales infectieuses / Elaboration of a Semi-Automatic Method for Identification and Analysis of Signals of Emergence of Animal Infectious Diseases at International Level

Arsevska, Elena 31 January 2017 (has links)
La veille en santé animale, notamment la détection précoce de l'émergence d'agents pathogènes exotiques et émergents à l'échelle mondiale, est l'un des moyens de lutte contre l'introduction de ces agents pathogènes en France.Récemment, il y a eu une réelle prise de conscience par les autorités sanitaires de l'utilité de l'information non-structurée concernant les maladies infectieuses publiée sur le Web.C'est dans ce contexte que nous proposons un outil de veille basé sur une méthode de fouille de textes pour la détection, collecte, catégorisation et extraction de l'information sanitaire à partir des donnés textuelles non structurées (articles médias) publiées sur le Web.Notre méthode est générique. Toutefois, pour l'élaborer, nous l'appliquons à cinq maladies animales infectieuses exotiques : la peste porcine africaine, la fièvre aphteuse, la fièvre catarrhale ovine, la maladie du virus Schmallenberg et l'influenza aviaire.Nous démontrons que des techniques de fouille de textes, complétées par les connaissances d'experts du domaine, sont la fondation d'une veille sanitaire du Web à la fois efficace et réactive pour détecter des émergences de maladies exotiques au niveau international.Notre outil sera utilisé par le dispositif de veille sanitaire internationale en France, et facilitera la détection précoce de signaux de dangers sanitaires émergents dans les articles médias du Web. / Monitoring animal health worldwide, especially the early detection of outbreaks of emerging and exotic pathogens, is one of the means of preventing the introduction of infectious diseases in France.Recently, there is an increasing awareness among health authorities for the use of unstructured information published on the Web for epidemic intelligence purposes.In this manuscript we present a semi-automatic text mining approach, which detects, collects, classifies and extracts information from non-structured textual data available in the media reports on the Web. Our approach is generic; however, it was elaborated using five exotic animal infectious diseases: african swine fever, foot-and-mouth disease, bluetongue, Schmallenberg, and avian influenza.We show that the text mining techniques, supplemented by the knowledge of domain experts, are the foundation of an efficient and reactive system for monitoring animal health emergence on the Web.Our tool will be used by the French epidemic intelligence team for international monitoring of animal health, and will facilitate the early detection of events related to emerging health hazards identified from media reports on the Web.
4

Étude des conditions de l'émergence du phytophthora alni sur l'aulne glutineux / Study of the emerging conditions of the alder decline pathogen Phytophthora alni

Aguayo Silva, Jaime Cristián 09 November 2012 (has links)
Depuis les années 1990, l'aulne glutineux, espèce clé des ripisylves, est affecté par un oomycète qui cause son dépérissement : Phytophthora alni subsp. alni (Paa). La genèse de Paa est liée à un événement d'hybridation interspécifique entre deux espèces proches, improprement nommées P. alni subsp. uniformis (Pau) et P. alni subsp. multiformis (Pam), car initialement considérées comme des variants de Paa. L'objectif de cette thèse était d'identifier les facteurs ayant pu jouer un rôle dans l'émergence de la maladie en Europe. Par une approche de génétique des populations, nous avons montré que Pau est une espèce invasive en Europe, probablement originaire d'Amérique du Nord. Après son introduction, l'hybridation de Pau avec Pam serait l'un des facteurs essentiels de l'apparition de Paa. Nos résultats confirment que Paa aurait été généré suite à des hybridations récurrentes, qui ont structuré géographiquement les populations en Europe. L'analyse de la variabilité génétique de Paa, révélée par des marqueurs microsatellites, a toutefois montré un faible polymorphisme, avec un génotype dominant largement répandu en Europe. Par ailleurs grâce à la modélisation, nos résultats ont établi que le dépérissement du houppier des aulnes est lié à la température. En particulier l'incidence de la maladie augmente lors des hivers doux, qui pourraient favoriser la survie du mycélium de Paa, celui-ci ne présentant pas de structure de survie hivernale (chlamydospores ou oospores). La température estivale joue également un rôle, plus complexe à interpréter. On constate en effet que l'incidence de la maladie diminue avec l'augmentation des températures estivales, mais ce phénomène pourrait dépendre d'autres facteurs tels que l'état physiologique des arbres ou le type de communautés microbiologiques présentes dans les sols. Inversement, le phénomène de guérison des arbres est favorisé par des températures hivernales basses et par des températures estivales élevées. L'émergence de la maladie ne peut pas être expliquée par le changement climatique. Cependant, une augmentation des températures hivernales dans le futur dans le cadre du changement climatique aggraverait très probablement l'épidémie / Since the early 1990's alder decline caused by the oomycete Phytophthora alni subsp. alni (Paa) is one of the most important threats to riparian ecosystems in Europe. The emergence of Paa is related to an interspecific hybridization event between two related species -initially considered as Paa variants- misnamed as Phytophthora alni subsp. uniformis (Pau) and Phytophthora alni subsp. multiformis (Pam). The objective of this thesis was to identify the factors that may have contributed to the emergence of the disease in Europe. Following a population genetics approach we showed that Pau is likely to be an invasive species in Europe, probably native to North America. Its introduction would have enabled hybridization with Pam and, consequently be a major cause on the emergence of Paa. Our results confirm that Paa has arisen from several hybridization events, which have geographically structured its European populations. Paa's genetic variability, revealed by microsatellite markers, showed low levels of polymorphism, with a dominant genotype scattered throughout Europe. In addition, a modelling approach revealed that alders' crown decline is linked to temperature. In particular, the disease incidence increases during mild winters which favours mycelium survival as Paa does not produce resistant spores (chlamydospores or oospores). The effect of summer temperatures is more complex to explain. Disease incidence decreases when summer temperatures are higher, but this phenomenon can also be linked to the physiological conditions of trees or changes in soil microbiological communities. Conversely, tree recovery is favoured by lower winter and higher summer temperatures. Climate change does not explain the emergence of the disease. However, increases in winter temperatures du to climate change may strengthen the epidemic
5

Dispers?o da febre amarela entre primatas n?o-humanos durante epizootia no Rio Grande do Sul : entendendo o papel de fatores abi?ticos, da paisagem e da presen?a de animais imunes para propor cen?rios futuros de reemerg?ncia da doen?a

Almeida, Marco Ant?nio Barreto de 22 March 2018 (has links)
Submitted by PPG Zoologia (zoologia-pg@pucrs.br) on 2018-08-01T18:22:00Z No. of bitstreams: 1 Almeida MAB___TESE___VERS?O FINAL.pdf: 2953118 bytes, checksum: 99cbefa9c38c7969abce4bafc4b20d54 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-08-02T17:55:11Z (GMT) No. of bitstreams: 1 Almeida MAB___TESE___VERS?O FINAL.pdf: 2953118 bytes, checksum: 99cbefa9c38c7969abce4bafc4b20d54 (MD5) / Made available in DSpace on 2018-08-02T18:39:41Z (GMT). No. of bitstreams: 1 Almeida MAB___TESE___VERS?O FINAL.pdf: 2953118 bytes, checksum: 99cbefa9c38c7969abce4bafc4b20d54 (MD5) Previous issue date: 2018-03-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Nonhuman primates (NHP) are susceptible to many arboviruses, including the yellow fever (YF) virus. Although native to Africa, this virus found susceptible NHP and competent mosquito vectors for maintaining its transmission in American forests. A high sensitivity of NHP to YF led health agencies to monitor these animals as a way of monitoring the disease in Brazil. The State of Rio Grande do Sul (RS) began this surveillance in 2002, which has detected the arboviruses Oropouche and Saint Louis (SLEV) and a YF epizootic that killed more than 2,000 NHP (Alouatta caraya and A. guariba clamitans) between 2008 and 2009. The objectives of this PhD thesis research were to generate models of niche suitability for YF based on that epizootic and prospect arboviruses in NHP in northwestern RS. The maximum entropy algorithm - Maxent was used to generate distribution models of Alouatta spp. and the mosquito vector Haemagogus leucocelaenus. Together with climatic, topographic and vegetative variables, these models served as predictor layers to model the occurrence of the disease based on the points of death of NHP of YF. The most influential variables in the YF models were the variation in air humidity, distribution of Alouatta spp. and maximum wind speed followed by mean annual rainfall and maximum temperature. Therefore, support for the influence of the rainfall regime and the ambient temperature on the cycle of jungle YF was found. Wind speed and direction can play an important role in the dispersal of infected mosquitoes and, consequently, the virus. The models based on the occurrence of dead NHP in the first months of the epizootic identified suitable areas to where the disease spread a few months later. In addition, 19 arboviruses were prospected in 40 blood (viral isolation and PCR) and serum (hemagglutination inhibition and neutralization tests [NT]) samples collected from 26 black howler monkeys (A. caraya) belonging to three populations in four field campaigns in the municipality of Santo Ant?nio das Miss?es, RS, between 2014 and 2016. There was no detection of circulating virus, but antibodies to Flavivirus SLEV and Ilh?us and Phlebovirus Icoaraci was found by NT. Evidence of the contact with Ilh?us and Icoaraci are the southernmost records in Brazilian NHP. An increase in antibodies to SLEV detected between two consecutive captures of the same individual is compatible with a recent contact with the virus. An adult male captured in one of the areas presented concomitant infection by the Oropouche, SLEV and YF viruses by NT. Further studies are necessary to understand the role played by NHP and other vertebrates in the circulation of arboviruses in the region, to assess potential risks to NHP and public health, and to identify the driving forces responsible for the dispersal of the YF virus during epizootics in wildlife populations. / Os primatas n?o-humanos (PNH) s?o suscet?veis a diversos arbov?rus, incluindo o v?rus da febre amarela (FA). Embora origin?rio da ?frica, esse v?rus encontrou PNH suscet?veis e mosquitos vetores competentes para sua transmiss?o em matas nas Am?ricas. Uma alta sensibilidade dos PNH ? FA levou ?rg?os de sa?de a monitorar esses animais como forma de vigiar a doen?a no Brasil. O Estado do Rio Grande do Sul (RS) iniciou essa vigil?ncia em 2002, a qual detectou os arbov?rus Oropouche e Saint Louis (SLEV) e uma epizootia de FA que matou mais de 2000 PNH (Alouatta caraya e A. guariba clamitans) entre 2008 e 2009. A presente tese de doutorado teve como objetivos gerar modelos de adequabilidade ambiental para FA com base nessa epizootia e prospectar arbov?rus em PNH no noroeste do RS. Foi utilizado o algoritmo de m?xima entropia ? Maxent para gerar modelos de distribui??o de Alouatta spp. e do mosquito vetor Haemagogus leucocelaenus. Esses modelos serviram como camadas preditoras para, junto a vari?veis clim?ticas, topogr?ficas e vegetacionais, modelar a ocorr?ncia da doen?a baseada nos pontos de morte de PNH por FA. As vari?veis mais influentes nos modelos da FA foram a varia??o na umidade do ar, a distribui??o de Alouatta spp. e a velocidade m?xima dos ventos, seguidas pela precipita??o m?dia anual e a temperatura m?xima. Portanto, foi confirmado suporte para a influ?ncia do regime de chuvas e da temperatura ambiente no ciclo da FA silvestre. A velocidade e a dire??o do vento devem desempenhar um importante papel na dispers?o de mosquitos infectados e, consequentemente, do v?rus. Os modelos baseados na distribui??o espacial de PNH mortos nos primeiros meses da epizootia identificaram ?reas adequadas para onde a doen?a avan?ou poucos meses mais tarde. Tamb?m foram prospectados 19 arbov?rus em 40 amostras de sangue (isolamento viral e PCR) e soro (inibi??o da hemaglutina??o e testes de neutraliza??o [NT]) coletadas em quatro campanhas de campo entre 2014 e 2016 de 26 bugios-pretos (A. caraya) de tr?s popula??es no munic?pio de Santo Ant?nio das Miss?es, RS. N?o houve detec??o de v?rus circulante, mas sim de anticorpos para os Flavivirus SLEV e Ilh?us e o Phlebovirus Icoaraci por NT. As evid?ncias de contato com Ilh?us e Icoaraci s?o as primeiras em PNH no extremo sul do Brasil. Um aumento de anticorpos para SLEV detectado entre duas capturas consecutivas do mesmo indiv?duo ? compat?vel com um contato recente com o v?rus. Um macho adulto capturado em uma das ?reas apresentou infec??o concomitante pelos v?rus Oropouche, SLEV e FA por NT. Mais estudos s?o necess?rios para compreender o papel de PNH e outros vertebrados na circula??o de arbov?rus na regi?o, avaliar poss?veis riscos para PNH e a sa?de humana e identificar as for?as motrizes respons?veis pela dispers?o do v?rus da FA durante epizootias em popula??es selvagens.

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