During active surveillance for transmissible spongiform encephalopathies (TSEs) in sheep, an initial reactor was detected using a rapid test on a brain sample. Immunohistochemistry confirmed an atypical TSE presentation that closely resembled the previously described Nor98 cases. Sequencing of the prnp gene confirmed the ARQ/AHQ genotype with the L141F mutation at codon 141 associated with this phenotype. The head, including the brain and cranial lymphoid tissues, was sampled and examined thoroughly. Non-purulent encephalitis, with ectopic lymphoid follicle formation within the brain, was diagnosed concomitant to the TSE. When scrapie-associated prion protein (PrPsc) deposition was studied by immunohistochemistry there was a noticeable lack of lymphotropism. The distribution of PrPsc in the brain differed considerably from that of classical scrapie cases. Astrogliosis and microgliosis were demonstrated by histochemical procedures.
|Number of pages||6|
|Publication status||Published - 1 Aug 2008|
- Atypical scrapie
- PrP sc