New research published Monday suggests BSE may be caused by a virus, and not prions as previously thought. More investigation is needed to confirm this study.
Researchers reported that they found virus-like particles in mouse nerve cells infected with two brain-wasting diseases similar to mad cow disease, but found no traces of the particles in uninfected cells. Lead author Dr. Laura Manuelidis, a neuropathologist at Yale University, said the finding suggested that prions in infected brains were the result of a viral infection and not the cause of the disease.
Several brain researchers were skeptical about Manuelidis’ findings, published in the Proceedings of the National Academy of Sciences. “It’s very remarkable that we only see these particles after infection of these cells,” said Bob Rohwer, director of the Molecular Neurovirology Laboratory at the Veterans Affairs Medical Center in Baltimore, who was not involved in the study. “But the evidence that they are in fact the infectious agent responsible is still highly circumstantial.”
The prion theory of mad cow disease proposes that a normal protein spontaneously misfolds, starting a cascade of abnormal changes in other proteins. In Manuelidis’ previous experiments, prions did not appear until late in the progression of spongy brain diseases.