May 23, 2004

scientists comment on finding of prions in sheep, as published in Nature Medicine

An expert commented on research in Nature Medicine showing that sheep muscle contains a very low level of infectious prion agent.

Dr Roger Morris, working on the molecular basis of vCJD at Kings College London, said:

“The demonstration that sheep mucsle (i.e. your Sunday leg of lamb or lamb chops) has a very low level of infectious prion agent is not in itself disturbing. The disease in sheep is called scrapie, and in this country we have a few centuries experience of eating sheep brain and spinal cord (the marrow of chops) without any indication that it causes any variant of CJD in man. Sheep scrapie appears to be safe for us.”

“There is strong evidence, which most scientists find convincing, that the cattle version of this disease (BSE, or mad cow disease) has passed to man in the UK, at a very low frequency. Could we extrapolate from sheep to suggest that our beef is unsafe? Studies so far have not found BSE in beef muscle (roast beef, steaks etc). Even should they occur there at low levels at the peak of the disease, cattle are killed for beef at around 18 months of age when they are too young to develop clinical disease. This paper is certainly not going to worry me when eating beef or lamb.”