Atypical/Nor98 scrapie infectivity in sheep peripheral tissues.
PLoS Pathog
; 7(2): e1001285, 2011 Feb 10.
Article
em En
| MEDLINE
| ID: mdl-21347349
ABSTRACT
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 PrP(Sc) 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.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Scrapie
/
Doenças dos Ovinos
/
Proteínas PrPSc
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Revista:
PLoS Pathog
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
França