Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues

PLoS Pathogens

Stéphanie Simon¹  Nathalie Morel¹  Annick Le Dur²  Vincent Beringue²  Hubert Laude²  Leonor Orge³  Sylvie L. Benestad⁴  Caroline Lacroux⁵  Fabien Corbière⁵  François Schelcher⁵  Claire Litaise⁵  Olivier Andréoletti⁵  Séverine Lugan⁵  Pierrette Costes⁵  Hugh Simmons⁶ 

[1] CEA, Service de Pharmacologie et d'Immunoanalyse, IBiTec-S, DSV, CEA/Saclay, Gif sur Yvette cedex, France;INRA UR892, Virologie et Immunologie Moléculaires, INRA, F-78350 Jouy-en-Josas, France;Laboratório Nacional de Investigação Veterinária, Lisboa, Portugal;National Veterinary Institute, Oslo, Norway;UMR INRA ENVT 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, Toulouse, France;VLA Weybridge, ASU, Addlestone, Surrey, United Kingdom

关键词: Scrapie;    Sheep;    Animal prion diseases;    Central nervous system;    Brainstem;    Muscle tissue;    Ruminants;    Cerebral cortex;   

DOI  :  10.1371/journal.ppat.1001285

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Atypical/Nor98 scrapie was first identified in 1998 in Norway. It is now considered as a worldwide disease of small ruminants and currently represents a significant part of the detected transmissible spongiform encephalopathies (TSE) cases in Europe. Atypical/Nor98 scrapie cases were reported in ARR/ARR sheep, which are highly resistant to BSE and other small ruminants TSE agents. The biology and pathogenesis of the Atypical/Nor98 scrapie agent in its natural host is still poorly understood. However, based on the absence of detectable abnormal PrP in peripheral tissues of affected individuals, human and animal exposure risk to this specific TSE agent has been considered low. In this study we demonstrate that infectivity can accumulate, even if no abnormal PrP is detectable, in lymphoid tissues, nerves, and muscles from natural and/or experimental Atypical/Nor98 scrapie cases. Evidence is provided that, in comparison to other TSE agents, samples containing Atypical/Nor98 scrapie infectivity could remain PrPSc negative. This feature will impact detection of Atypical/Nor98 scrapie cases in the field, and highlights the need to review current evaluations of the disease prevalence and potential transmissibility. Finally, an estimate is made of the infectivity loads accumulating in peripheral tissues in both Atypical/Nor98 and classical scrapie cases that currently enter the food chain. The results obtained indicate that dietary exposure risk to small ruminants TSE agents may be higher than commonly believed.

【 授权许可】

CC BY