Open AccessRecognition of the Nor98 Variant of Scrapie in the Swedish Sheep Population
Author(s) -
Dolores GavierWidén,
Maria Nöremark,
Sylvie L. Benestad,
Marion Simmons,
Lena Renström,
Bjørn Bratberg,
M. Elvander,
Carl Hård af Segerstad
Publication year - 2004
Publication title -
journal of veterinary diagnostic investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.529
H-Index - 78
eISSN - 1943-4936
pISSN - 1040-6387
DOI - 10.1177/104063870401600611
Subject(s) - scrapie , flock , ataxia , immunostaining , biology , population , pathology , immunohistochemistry , cerebellum , prion protein , genotype , virology , medicine , genetics , disease , gene , neuroscience , environmental health , paleontology
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.