Atypical/Nor98 scrapie: properties of the agent, genetics, and epidemiology

Sylvie Benestad , Jean-Noël Arsac , Wilfred Goldmann , Maria Nöremark

Atypical/Nor98 scrapie cases in sheep were diagnosed for the first time in Norway in 1998. They are now identified in small ruminants in most European countries and represent an increasingly large proportion of the scrapie cases diagnosed in Europe. Atypical/Nor98 scrapie isolates have shown to be experimentally transmissible into transgenic mice and sheep but the properties of the TSE agent involved, like its biological and biochemical features, are so clearly distinct from the agent involved in classical scrapie that they have provided a challenging diagnostic for many years. No strain diversity has yet been identified among the atypical/Nor98 scrapie sample cases. The genetic predisposition of the sheep affected by atypical/Nor98 scrapie is almost inverted compared to classical scrapie, and the exact origin of this sporadic TSE strain is still speculative, but a spontaneous, non-contagious origin, like sporadic Creutzfeldt-Jakob disease in humans, can not be excluded. Further transmission and epidemiological studies are needed to better address this hypothesis.

Mots clés: atypical scrapie; Nor98; transmissible spongiform encephalopathies TSE; genetics; epidemiology

Domaines: Biologie moléculaire; Génétique animale; Biologie cellulaire; Interactions cellulaires [q-bio.CB]; Microbiologie et Parasitologie; Immunologie; Neurosciences [q-bio.NC]; Santé publique et épidémiologie; Biologie animale

Sylvie Benestad, Jean-Noël Arsac, Wilfred Goldmann, Maria Nöremark. Atypical/Nor98 scrapie: properties of the agent, genetics, and epidemiology. Veterinary Research, 2008, 39 (4), pp.1-14. ⟨10.1051/vetres:2007056⟩. ⟨hal-00902913⟩