This investigation studied the maternal transmission of scrapie in she
ep by using embryo transfer to examine the viability of highly suscept
ible offspring derived from scrapie-affected and uninfected donors. Th
e study also examined the effect of washing the embryos, Scrapie occur
red in both washed and unwashed embryo-derived Sip sAsA progeny from b
oth groups of donor ewes, As a result, the earlier observation that sc
rapie might pass via the unwashed embryo to develop as disease in adul
t sheep has to be reassessed. Several other implications of the work a
re considered, including the possibility that natural scrapie is not p
urely a genetic disease.