Mad cow disease was probably spread to Britain by an infected antelope, a New Zealand scientist said today.
This means an epidemic could still break out in other countries despite current restrictions.
Mr Roger Morris, a professor of animal health at Massey University in Palmerston North, New Zealand, told reporters the animal was probably imported in the mid-1970s by a safari park in southwest England.
He said it made its way into the food chain when it was ground up for meat-and-bone meal and fed to cattle that were later infected and ground up for feed themselves.
There is a danger here that an epidemic may break out in other countries despite the British restrictions. There is quite a movement of wildlife around the world, Professor Massey said in a telephone interview.
Formally known as bovine spongiform encephalopathy, mad cow disease first swept through British herds in the 1980s. That led to the slaughter and burning of millions of animals and sparked a health scare when a fatal human form of the disease was detected.
Official data show that 90 people in Britain and two in France have died or are believed to have died from new variant Creutzfeldt-Jakob Disease, the human form of mad cow disease for which there is no cure.