title: Recognition of the Nor98 variant of scrapie in the Swedish sheep population.
abstract: Within the framework of the active surveillance for transmissible spongiform encephalopathies in sheep in Sweden, 4 cases of the atypical form of scrapie, Nor98, were identified during 2003. Nor98 is a recently recognized and poorly understood variant of scrapie, first described in Norway. The cases were positive by the rapid test (enzyme-linked immunosorbent assay). Immunohistochemical staining showed diffuse thin-granular staining of the cerebellar cortex. Western immunoblotting analysis of specimens of brain stem and cerebellum showed a light band of approximately 12 kDa. Typical scrapie was ruled out based on the confirmatory testing. The affected ewes were from 4 different flocks. They were between 7 and 9 years old. Two were of the ARQ/ARQ genotype, 1 ARR/ARQ, and 1 ARR/AHQ. Two ewes had shown ataxia, and the other 2 had no clinical signs. Whole-flock slaughter was applied, and testing of the flock mates did not reveal additional cases. Nor98 differs from typical scrapie in its epidemiology, frequency of genotypes of sheep affected, clinical signs, microscopic lesions, distribution of scrapie prion protein in the brain, and characteristics of the immunostaining and immunoblotting profiles.
authors.affiliation: National Veterinary Institute (SVA), Uppsala, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Gavier-Widén
authors.forename: M
authors.initials: M
authors.lastname: Nöremark
authors.forename: S
authors.initials: S
authors.lastname: Benestad
authors.forename: M
authors.initials: M
authors.lastname: Simmons
authors.forename: L
authors.initials: L
authors.lastname: Renström
authors.forename: B
authors.initials: B
authors.lastname: Bratberg
authors.forename: M
authors.initials: M
authors.lastname: Elvander
authors.forename: C Hård
authors.initials: CH
authors.lastname: af Segerstad
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D008970:Molecular Weight; D018620:PrPSc Proteins / Q000235:genetics / Q000378:metabolism*; D012608:Scrapie / Q000145:classification* / Q000175:diagnosis* / Q000378:metabolism; D012756:Sheep; D013548:Sweden
chemical_list: D018620:PrPSc Proteins