Accumulation of PrPd in the medulla of scrapie infected goats. (a) Abundant deposits of abnormal protein in the neuropil of the dorsal motor nucleus of the vagus nerve (DMNV) and adjacent structures, with occasional heavily labelled coalescing PrPd aggregates; serial samples of caudal medulla provided positive ELISA results. IHC with Bar224 PrP antibody and haematoxylin counterstaining, ×10. (b) Trace extracellular deposits (arrows) in the DMNV of a clinically healthy goat that provided negative ELISA results in serial samples of caudal medulla. IHC with Bar224 PrP antibody and haematoxylin counterstaining, ×20.