There is additional evidence to suggest a link between bovine spongiform encephalopathy and a fatal human brain disease that has killed 51 people in Europe.
A study published Dec 21, 1999 in the Proceedings of the National Academy of Science reportedly provides strong evidence that prions from BSE-infected cattle can infect humans and cause new variant Creuztfeldt-Jakob disease.
Researchers from the University of California-San Francisco and Western General Hospital in Edinburgh, Scotland used a genetically altered strain of mice with genes for the bovine prion protein. The mice were then inoculated with infected prions from diseased cattle.
Approximately 250 days later, the mice developed the disease.
Another group of genetically altered mice inoculated with prions from BSE-infected mice also developed the disease after about the same 250-day interval.
Authors of the study say that there is no species barrier for transmission from cattle to mice, implying that people with nvCJD could have gotten it from eating BSE-infected meat.
Investigators emphasized the importance that prions from human cases of nvCJD injected into mice caused an incubation period and pattern of brain damage similar to those caused by inoculation with prions from diseased cows.
Additionally, mice injected with scrapie developed a form of the disease but it "differed dramatically" from the infection linked to BSE.
"Our findings provide the most compelling evidence to date that prions from cattle with BSE have infected humans and caused fatal neurodegeneration," the study abstract stated.
Neither BSE nor nvCJD has been discovered in the United States.