NR AWCN
AU Buschmann,A.; Eiden,M.; Gretzschel,A.; Hoffmann,C.; Groschup,M.H.
TI TSE strain variability in sheep
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Oral sessions ORAL-23
PT Konferenz-Vortrag
AB Scrapie in sheep and goats has been known for centuries. Following transmission to rodents, at least six different primary scrapie strains have been isolated and characterised historically by analysing the incubation times and profiles of the histopathological lesion in the brains in a standard panel of inbred RIII, C57Bl and VM mice. The PrPsc signature in most of these classical scrapie isolates is rather similar in terms of its PK resistance and glycoform pattern in immunoblot. However, the intensified epidemiosurveillance of small ruminants in the EU since 2002 lead to the recognition of previously disregarded scrapie cases with atypical histopathological and immunohistochemical features and immunochemical PrPsc patterns in the brains of the affected animals. Nor98 (the first reported case of this kind) and SCR2 (an isolate dating back to 1989 in the UK and now recognised as such) are prototypes of the large majority of these atypical cases. Similar cases have been described in most EU member states which so far all seem to belong into the same category. Atypical scrapie is characterized by a lower resistance of the accumulated PrPsc to proteinase K digestion as compared to classical scrapie strains, explaining why the vast majority of these cases are not detected by most of the so far applied BSE rapid tests. The most obvious characteristics are the altered immunoblot profile comprising of at least 5 bands and including a small fragment of approx. 11 kDa that represents the core fragment of PrPsc. The anatomical distribution of PrPsc deposition also varies from classical scrapie, as the cerebellum is the most affected localisation, while the brainstem may be free of detectable PrPsc. The infectivity of such atypical scrapie cases has been demonstrated using two different transgenic mouse lines. However, the origin of this strain is still under discussion and a spontaneous occurrence cannot be ruled out.
AD Friedrich-Loeffler Institut, Institute for Novel and Infectious Emerging Diseases, Boddenblick 5a, 17493 Greifswald - Insel Riems, Germany. E-mail: martin.groschup@fli.bund.de
SP englisch
PO Italien