It is assumed that sheep and goats consumed the same
bovine spongiform encephalopathy (BSE)-contaminated meat and
bone meal that was fed to cattle and precipitated the BSE epidemic in the United Kingdom that peaked more than 20 years ago. Despite intensive surveillance for cases of BSE within the small ruminant populations of the United Kingdom and European Union, no instances of BSE have been detected in sheep, and in only two instances has BSE been discovered in goats. If BSE is present within the small ruminant populations, it may be at subclinical levels, may manifest as
scrapie, or may be masked by
coinfection with
scrapie. To determine whether BSE is potentially circulating at low levels within the European small ruminant populations, highly sensitive assays that can specifically detect BSE, even within the presence of
scrapie prion protein, are required. Here, we present a novel assay based on the specific amplification of BSE PrP(Sc) using the serial
protein misfolding cyclic amplification assay (sPMCA), which specifically amplified small amounts of ovine and caprine BSE agent which had been mixed into a range of
scrapie-positive brain homogenates. We detected the BSE
prion protein within a large excess of classical, atypical, and CH1641
scrapie isolates. In a blind trial, this sPMCA-based assay specifically amplified BSE PrP(Sc) within brain mixes with 100% specificity and 97% sensitivity when BSE agent was diluted into
scrapie-infected brain homogenates at 1% (vol/vol).