In experiments, researchers have infected monkeys and mice with mad cow disease by feeding them brain tissue from infected cattle. That clued in the scientific community that there was a danger in Britain years before the government acknowledged it. In the United States, there have been reports of related diseases in mink and deer. These are not mad cow disease, said prion researcher Judd Aiken of the University of Wisconsin, Madison, although all have been fatal. These animals did not get the disease from England, nor did they get it from eating beef.
Sheep can suffer from another prion disease called scrapie.
How the mink, deer and sheep acquire these prion diseases is not well understood. Nor is it known how easy it is to transmit the deer disease to humans who eat venison. Humans are thought to get new variant Creutzfeldt-Jakob disease by eating meat from infected animals. There is no evidence that a prion disease can be transmitted from person to person, unless they practice cannibalism. In New Guinea, people got a form of Creutzfeldt-Jakob disease, called kuru, from eating the bodies, including the brains, of their dead relatives.