Researchers then began to try to prove that BSE could be transmitted to humans. They injected brain extract from BSE-infected cattle into monkeys. Researchers then injected brain extract from BSE-infected cattle into mice and then repeated the experiment with brain extract from three people who had died from the disease. This was proof that BSE had jumped the species barrier to humans and that people could catch this TSE from eating beef. No one really knows how large the epidemic will be.
Estimates range from several hundred people to many thousands.
Researchers in the U.K. have recently developed a test that will detect the abnormal prion in a person's tonsils. Their tonsils will be tested for the prion.