title: Derivation of a scrapie-free sheep flock from the progeny of a flock affected by scrapie.
abstract: The Cheviot flock at the Institute for Animal Health's Neuropathogenesis Unit (npu) has endemic scrapie, which affects primarily vrq/vrq sheep and at high frequency. A new flock with a full range of PrP genotypes, including the highly susceptible vrq/vrq, has been produced on a separate site, from animals in the npu breeding flock, and it remains scrapie-free after eight years. In contrast, in a parallel flock at the npu farm, scrapie has reappeared after five years, although the animals were kept in separate accommodation from the scrapie-affected sheep. During this time the npu breeding flock continued to have scrapie cases. Although it is known that highly susceptible sheep can remain free of infection in a clean environment, this is the first report of the infection being removed successfully from the bloodlines of scrapie-affected sheep. The results confirm that scrapie is not a genetic disease dependent only on the PrP gene sequence, but requires both genetic susceptibility and an infectious agent.
authors.affiliation: Institute for Animal Health, Neuropathogenesis Unit, West Mains Road, Edinburgh.
authors.forename: J
authors.initials: J
authors.lastname: Foster
authors.forename: C
authors.initials: C
authors.lastname: McKenzie
authors.forename: D
authors.initials: D
authors.lastname: Parnham
authors.forename: D
authors.initials: D
authors.lastname: Drummond
authors.forename: W
authors.initials: W
authors.lastname: Goldmann
authors.forename: E
authors.initials: E
authors.lastname: Stevenson
authors.forename: N
authors.initials: N
authors.lastname: Hunter
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D001947:Breeding; D005260:Female; D020022:Genetic Predisposition to Disease; D008297:Male; D018620:PrPSc Proteins / Q000235:genetics* / Q000472:pathogenicity*; D012608:Scrapie / Q000235:genetics*; D012756:Sheep
chemical_list: D018620:PrPSc Proteins