LONDON - The sheep disease scrapie, believed to be the basis for the epidemic of mad cow disease, is not strictly genetic and may be partly caused an infectious agent, British scientists said yesterday.
"Here we present evidence that scrapie is not solely a genetic disease, as scrapie associated prion protein (genes) are present in sheep from Australia and New Zealand, both countries that are entirely free of scrapie," Dr Nora Hunter and colleagues at the Institute for Animal Health wrote in a letter to the science journal Nature.