Protection against mad cow disease

In 1996, during an epidemic of mad cow disease—bovine spongiform encephalopathy—in British cattle, epidemiologists predicted that up to 100,000 people could contract variant Creutzfeldt-Jakob disease (vCJD), a rapidly progressing, invariably fatal neurodegenerative condition, from infected beef. But that nightmarish scenario has not yet come to pass: 10 years later, only 151 cases of vCJD have been verified.

Laura M. Manuelidis, M.D. ’67, HS ’70, FW ’70, professor and chief of surgery (neuropathology), may have discerned why. Manuelidis and colleagues reported in Science in October that exposure to less-virulent strains of CJD may protect against infection with the newly evolved bovine strain. The team found that when neuronal cell cultures were infected with either a weak or sporadic form of CJD, or with agents that cause sheep scrapie, a disease similar to CJD, they resisted infection by the more-virulent strain.