Tonsillar biopsy and PrPSc detection in the preclinical diagnosis of scrapie

摘要: Preliminary findings have indicated that in naturally infected sheep, fully susceptible to scrapie (vRQ-homozygous), PrPSc can be detected the tonsils approximately one year before expected onset of clinical disease, whereas no immunostaining animals with a semi-resistant genotype. This paper describes technique for taking tonsillar biopsies from sheep and gives results completed experiment. In another experiment was even earlier comparable vRQ-homozygous born raised different surroundings. At three-and-a-half months age could three homozygous (VRQ/VRQ), but PrpSc at four similar sheep. eight all seven sampled VRQ/VRQ showed positive biopsies, none VRQ/ARQ heterozygotes any immunostaining; they were when 14 15 age. Biopsies VRQ/ARR negative throughout this period. On basis established or incubation period, thus live between one-third half more than oneand- a-half years signs normally appear both these genotypes.