Vers une harmonisation écologique et sociale en milieu rural: le cas des porcheries industrielles au Québec est un rapport de stage qui analyse en sept portraits les sources, les causes et les impacts des conflits générés par la production porcine intensive au Québec. Portrait politique: Une p'tite loi, une p'tite subvention, beaucoup de dégradation! De la colonisation à la conquête des marchés d'exportation, les gouvernements du Québec et du Canada ont adopté et défendu une série de Lois et de Règlements pour soutenir et financer le développement de la production animale industrielle. Des études montrent que ces choix se sont fait au détriment, entre autres, d'une qualité de vie sociale et de la protection de l'environnement, et qu'ils soulèvent d'importantes questions éthiques. Des municipalités et des MRC ont développé des approches réglementaires originales, majoritairement refusées par le Gouvernement du Québec. Mais la dégradation rapide du climat social et de l'environnement pousse les législateurs à arrimer désormais la production porcine industrielle aux exigences du « développement durable ». Portrait économique: Toujours plus cher, toujours plus précaire! Malgré de nombreux programmes de soutien financier à la production porcine et l'augmentation des cheptels, la ferme porcine familiale est en voie de disparition. Seules les grandes entreprises et les intégrateurs tirent avantageusement leur épingle du jeu du marché du porc. Et encore. Les présentes difficultés de la Coopérative fédérée du Québec laisse entrevoir que le gouffre financier n'a pas fini d'aspirer les capitaux des agriculteurs et les deniers publics. L'argent dépensé en vaut-il vraiment l'investissement? Portrait agronomique: Un porc de haute technologie. C'est en faisant confiance à la techno-science que les producteurs de porcs espèrent conserver leur place sur les marchés internationaux et contrer les oppositions sociales. L'industrie porcine introduit dans les campagnes des lignées porcines modifiées donnant naissance à des ultra-animaux qu'il faut vacciner, édenter, castrer. A travers la modification génétique des semences et de la génétique animale, la science tente aussi de favoriser une meilleure performance environnementale et sanitaire des porcheries. Portrait environnemental: L'insoutenable pollution. Les élevages intensifs de porcs, associés à la production intensive de maïs et autres cultures céréalières, ont contribué à la détérioration de la qualité de l'eau, de l'air, du couvert forestier, des sols. Ils participent à l'augmentation des gaz à effet de serre et à la dissémination des organismes génétiquement modifiés qui affectent la biodiversité des plantes et des semences. L'insupportable présence d'odeurs a soulevé la colère des citoyens qui se sont alliés aux protecteurs des milieux de vie, des espèces vulnérables et de la santé publique pour alerter le public et les instances gouvernementales. Les nouvelles technologies et les objectifs de développement durable serviront-ils la cause environnementale? Portrait en santé publique : L'effet domino! Dans plusieurs régions, le développement de l'industrie porcine touche plusieurs aspects de la santé physique et mentale des populations et affecte fortement la biodiversité. En effet, l'industrie porcine a introduit de nombreux polluants et résidus dans la nature: écoulement de lisier, pesticides, antibiotiques et autres substances dans les cours d'eau et nappes phréatiques, transport et tranfert d'OGM; elle a porté atteinte à l'organisation de la vie communautaire, dévalorisé les connaissances culturelles et détérioré les relations sociales entre les citoyens. Les professionnels de la santé s'inquiètent des conséquences de l'accumulation et de l'effet synergique de toutes ces substances et des problèmes qui en découlent sur la santé des populations, tant rurale qu'urbaine. Portrait social: Vivre ensemble en harmonie. En 2006, un peu partout, ce n'est plus l'agriculture qui fait vivre la communauté régionale, mais la communauté régionale qui fait vivre -ou non -l'agriculture. Le nombre d'agriculteurs poursuit son déclin et plusieurs milieux ruraux vivent une crise d'identité profonde. Les propriétaires d'une ferme sont-ils des artisans, des paysans, des agriculteurs ou des producteurs agricoles? S'agit-il d'entrepreneurs, de grands propriétaires terriens, de gentlemen farmers , de néoruraux, de résidants qui ne pratiquent aucune activité agricole, pas même de jardinage? Le droit de produire, sur lequel s'appuie l'industrie porcine, doit être redéfini afin de pouvoir habiter la campagne en respectant et valorisant ses diverses fonctions. C'est le véritable enjeu de la cohabitation sociale harmonieuse en milieu rural. Portrait culturel: Mon pays, mes racines, mon patrimoine. L'identité des Québécois s'est modelée à partir de sa culture paysanne et de sa relation à la terre, même si la manière de l'exprimer a grandement évolué depuis 50 ans. La préservation et la protection du paysage, du patrimoine, des savoir-faire et des traditions culturelles et alimentaires sont au coeur de la lutte citoyenne contre les porcheries industrielles. Une nouvelle génération de consommateurs exprime son attachement à ces valeurs culturelles en consommant différemment.

The prevention and control of salmonellae in commercial swine operations are becoming increasingly important. The current approach focuses on identifying sources and/or origins of salmonellae contamination before swine are processed for human consumption. The objective of the current study was to assess strain variability among salmonellae grouped by serotype and to determine common origins of contamination (farm or slaughter plant). Salmonellae were previously collected from swine at slaughter, serotyped by the National Veterinary Services Laboratory and stored at - 70??C. Pulsed-field gel electrophoresis (PFGE) was performed to genotypically characterize serotypic isolates using restriction endonuclease XbaI. Dendrogram comparisons were also used to assess genotypic similarity when multiple genotypes existed. This study found PFGE to be more discriminatory than serotyping indicating that multiple genotypic strains existed among selected serotypes. On the basis of PFGE results alone, origins of contamination could not be determined in this study. It is suggested by the author, that origins of contamination could be further defined pending future research, in which in-depth longitudinal studies are included. When used as an adjunct to conventional typing methods, PFGE may prove to be a substantial subtyping system in epidemiologic investigations to identify point-of-entry contaminants to the food chain.

The transfer of a desired gene to several types of target tissues has been accomplished successfully in the past using existing Adeno-associated viruses (AAVs). Also, it has recently been shown that AAV can stimulate robust antibody responses due to long-term transgene expression or abolishment of transgene product by cell-mediated immune responses, suggesting the potential use of AAVs as vaccines. Most humans already have pre-existing immunity to common AAV serotypes making novel AAVs of low seroprevalence attractive as gene transfer or vaccine vehicles. This thesis describes my primary research objectives that included the isolation of novel AAV serotypes based on AAV DNA sequences from porcine tissues, novel AAV vector production, and biological characterization of porcine AAVs in vitro and in vivo. This was followed by evaluating immune responses in mice vaccinated with porcine AAV vectors expressing the hemagglutinin (HA) from the avian influenza A/Hanoi/30408/2005 (H5N1) strain. These findings show that low seroprevalence porcine AAV vectors were able to efficiently transduce a wide range of cells and tissues. The porcine vectors also performed well as vaccine candidates and were efficient at stimulating host immune responses. Although porcine vectors were successful as vaccines, further studies involving long term gene expression by porcine AAVs is still necessary to confirm their role as gene therapy vehicles.

The transfer of a desired gene to several types of target tissues has been accomplished successfully in the past using existing Adeno-associated viruses (AAVs). Also, it has recently been shown that AAV can stimulate robust antibody responses due to long-term transgene expression or abolishment of transgene product by cell-mediated immune responses, suggesting the potential use of AAVs as vaccines. Most humans already have pre-existing immunity to common AAV serotypes making novel AAVs of low seroprevalence attractive as gene transfer or vaccine vehicles. This thesis describes my primary research objectives that included the isolation of novel AAV serotypes based on AAV DNA sequences from porcine tissues, novel AAV vector production, and biological characterization of porcine AAVs in vitro and in vivo. This was followed by evaluating immune responses in mice vaccinated with porcine AAV vectors expressing the hemagglutinin (HA) from the avian influenza A/Hanoi/30408/2005 (H5N1) strain. These findings show that low seroprevalence porcine AAV vectors were able to efficiently transduce a wide range of cells and tissues. The porcine vectors also performed well as vaccine candidates and were efficient at stimulating host immune responses. Although porcine vectors were successful as vaccines, further studies involving long term gene expression by porcine AAVs is still necessary to confirm their role as gene therapy vehicles.

This thesis reports for the first time the detection of porcine circovirus virus (PCV) in the Australian pig herd. PCV DNA was detected in the tissues of pigs from several Australian states using a multiplex polymerase chain reaction (PCR) assay, the primers for which were based on the sequence of PCV1 and PCV2 strains detected in North America and Europe. PCV type 1 or 2 was detected in 80 of 367 (21.7%) pigs tested. In the 80 positives, both PCV1 and PCV2 were detected in 14 samples. Virus was detected in pigs from all states from which samples were obtained: Western Australia, South Australia, New South Wales and Queensland. The complete genomes of 13 strains of Australian PCV were sequenced. Analysis of the data indicated there was extremely high homology between the Australian strains of PCV1 and PCV2 and previously published sequences of PCV1 and PCV2 strains from North America and Europe.There were no consistent differences between the genome of the Australian strains and strains in North America and Europe. The widespread occurrence of PCV in the tissues of pigs was confirmed by a small scale serological study of the Western Australian pig herd using an immunofluorescence assay, which did not discriminate antibody to PCV1 and PCV2. This assay detected PCV antibody in 11 of 14 pig herds in Western Australia, with a prevalence rate in positive herds varying from 25 to 47%, but it was unable to differentiate antibody to PCV1 and PCV2. A PCV2-specific recombinant viral capsid protein was produced in insect cells with a baculovirus expression system and this was used to develop a PCV2-specific ELISA and a Western immunoblotting assay. These assays were applied to samples from a national pig serum bank and detected PCV2 antibody in 33% of 3933 serum samples. The highest seroprevalence to the recombinant PCV2 capsid antigen was detected in the samples from Victoria where there was a 51.3% seroprevalence rate, and the lowest in Western Australia where there was an 11.4% seroprevalence rate. An in situ hybridisation (ISH) technique was developed for the detection of PCV in tissues of infected pigs and infected cell cultures. A monoclonal antibody specific for the capsid protein of PCV2 was also produced and has application for the development of immunocytochemical procedures for the detection of PCV2 in tissues and cell cultures. The high prevalence of PCV in the Australian pig herd and the absence of reports of PMWS suggested that the Australian strains of PMWS detected may have been of low virulence. To examine the pathogenicity of Australian strains, two animal experiments were conducted where the type species of PCV1 present in persistently-infected PK15 pig kidney cells and an Australian PCV2 strain were cultured in vitro in cell cultures and inoculated into weaner pigs. As expected, the PCV1 replicated well in pigs but did not result in the induction of clinical signs or lesions in the inoculated pigs. The inoculation into weaner pigs of cell culture replicated PCV2 with an apparent virus titre of 103 virus particles/mL resulted in infection of only some of the inoculated pigs and it was concluded that the PCV2 inoculum contained insufficient virus to infect all pigs into which it was inoculated. The PCV2 did not induce any disease syndrome and could not be visualised in tissue sections of infected pigs using immunohistochemical techniques. In conclusion, techniques were developed for the detection of PCV in the Australian pig herd. PCV of both genetic types were detected at prevalence rates similar to those reported in other countries where PMWS has occurred, and the widespread occurrence of PCV was confirmed by serological assays. The PCV strains present were genetically indistinguishable from those present in North America and Europe. The reason for the absence of PMWS in Australia is most likely not due to differences in the characteristics of the PCV strains present.