Apparently, cows can have the prion without sheep being involved. If it were a prion that came "whole" from sheep to human (without cow) then we would have a big problem with "mad sheep disease" going to humans. There are, however, a number of similar "prion" diseases in various animals and humans that have been recognized for a long time, but these are independent of any beef involvement. Ultimately, "mad cow" may be related to (or triggered by) a similar sheep version, but it can arise independently via generation of the prion in the cow's body, perhaps from other cows, or the environment.
Said another way, if they find prions anywhere (human, sheep, cow) which cause problems, genetic modification is the way to eliminate them, since we know how they are made. The key is now we have documented the movement of prions into humans for the troublesome version, which moves from cow to human. That is an outstanding achievement; we are a step away from eradicating this problem by engineering out prions in cows and other animals.
You said:
But wasn't it the point that cows originally caught the disease from being fed with additives made from sheep? |
