International audience ; Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and ''cases'' that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and ''cases'' that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
In the moving context of research on animal health, a collective discussion has been carried out on its issues, special features and synergism with biomedical research. Strongly enhanced by WHO, FAO and OIE, the issues of animal health are important and deal with food security, agriculture economics and all economical activities that follow from it. Others are related to public health (zoonoses, xenobiotics, antimicrobial resistance), environment and animal welfare. Research on animal health has got special features concerning methodology and scientific questions, among others the particular biological nature of domestic species and breeding practices. Scientific questions are not similar to those of biomedical research, even if dealing with the same pathogens; connected to the other animal sciences (genetics, physiology, animal breeding), research on animal health takes root in a very specific agricultural and economical reality. Nevertheless, generic and methodological synergies do exist with biomedical research, particularly concerning biological tools and models. Some domestic species like pig have functional similarities with Humans, better than with mouse or rat. Thus, the peculiarity of research on animal health compared to biomedical research should be considered in its organisation, evaluation and funding, through a political recognition of specific issues. Simultaneously, the one health approach should facilitate a thorough collaboration between biomedical research and research on animal health, at the levels of research teams and research programmes. ; Dans le contexte très évolutif de la recherche en santé animale, une réflexion sur ses enjeux, ses spécificités et ses synergies avec la recherche biomédicale, a été conduite à l'initiative de l'INRA. Affirmés au premier chef par l'OMS, la FAO et l'OIE, les enjeux en santé animale, hors des maladies transmissibles à l'Homme, sont énormes et touchent à la sécurité alimentaire, l'économie de l'agriculture et l'ensemble des activités économiques qui en ...
Dans le contexte très évolutif de la recherche en santé animale, une réflexion sur ses enjeux, ses spécificités et ses synergies avec la recherche biomédicale, a été conduite à l'initiative de l'INRA. Affirmés au premier chef par l'OMS, la FAO et l'OIE, les enjeux en santé animale, hors des maladies transmissibles à l'Homme, sont énormes et touchent à la sécurité alimentaire, l'économie de l'agriculture et l'ensemble des activités économiques qui en découlent. S'y ajoutent les enjeux de santé publique (zoonoses, xénobiotiques, antibiorésistance), environnementaux et de bien-être animal. La recherche en santé animale présente des spécificités d'ordre méthodologique et scientifique, liées notamment aux particularités biologiques des espèces domestiques et aux pratiques d'élevage. Elle n'a pas les mêmes questionnements scientifiques qu'en biologie humaine même lorsqu'elle traite des mêmes agents pathogènes et, connectée aux autres sciences animales (génétique, physiologie, zootechnie), elle s'enracine dans une réalité agricole et économique très spécifique. Des synergies génériques et méthodologiques existent néanmoins avec la recherche biomédicale, en particulier autour des outils et des modèles biologiques. Certaines espèces domestiques (tel le porc) présentent en outre des similitudes fonctionnelles avec l'Homme, plus que le rongeur de laboratoire. Ainsi la singularité de la recherche en santé animale par rapport à la recherche en biologie humaine devrait être prise en compte dans son organisation, son évaluation et son financement, via une politique de reconnaissance des enjeux spécifiques. Simultanément, l'approche one health devrait faciliter une collaboration approfondie entre recherche en biologie humaine et recherche en santé animale, à l'échelle des équipes ou des programmes. ; In the moving context of research on animal health, a collective discussion has been carried out on its issues, special features and synergism with biomedical research. Strongly enhanced by WHO, FAO and OIE, the issues of animal health are important and deal with food security, agriculture economics and all economical activities that follow from it. Others are related to public health (zoonoses, xenobiotics, antimicrobial resistance), environment and animal welfare. Research on animal health has got special features concerning methodology and scientific questions, among others the particular biological nature of domestic species and breeding practices. Scientific questions are not similar to those of biomedical research, even if dealing with the same pathogens; connected to the other animal sciences (genetics, physiology, animal breeding), research on animal health takes root in a very specific agricultural and economical reality. Nevertheless, generic and methodological synergies do exist with biomedical research, particularly concerning biological tools and models. Some domestic species like pig have functional similarities with Humans, better than with mouse or rat. Thus, the peculiarity of research on animal health compared to biomedical research should be considered in its organisation, evaluation and funding, through a political recognition of specific issues. Simultaneously, the one health approach should facilitate a thorough collaboration between biomedical research and research on animal health, at the levels of research teams and research programmes.
