MOLECULAR SCREENING OF SHEEP FOR BOVINE SPONGIFORM ENCEPHALOPATHY

Bovine spongiform encephalopathy (BSE) may have transmitted to sheep t hrough feed and pose a risk to human health. Sheep BSE cannot be clini cally distinguished from scrapie, and conventional strain typing would be impractical on a significant scale. As human prion strains can be distinguished by differences in prion protein (PrPSc) conformation and glycosylation we have applied PrPSc typing to sheep. We found multipl e Western blot patterns of PrPSc in scrapie, consistent with the known scrapie strain diversity in sheep. Sheep passaged BSE showed a PrPSc banding pattern similar to BSE passaged in other species [Collinge, J. , Sidle, K.C.L., Meads, J., Ironside, J. and Hill, A.F., Nature, 383 ( 1996) 685-690], both in terms of fragment size following proteinase K cleavage and abundance of diglycosylated PrP. However, none of the his torical or contemporary scrapie cases studied had a PrPSc type identic al to sheep BSE. While more extensive studies, including sheep of all PrP genotypes, will be required to fully evaluate these findings, thes e results suggest that large scale screening of sheep for BSE may be p ossible. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.