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Researchers Develop Experimental Therapy for Mad Cow Disease

Mad cow disease, which can infect humans, is caused by an infectious protein. Until recently, there has been no treatment for mad cow and other so-called prion diseases, which lead to rapid dementia and death. Now, researchers have apparently cured the disease in newly infected mice. VOA's Jessica Berman reports.

The public first became aware of mad cow disease in the 1980s, when cows in Britain started coming down with a mysterious fatal, neurological illness. Then in the 1990's, a handful of people who had eaten infected beef also fell ill with the same symptoms and died of a disease called variant Creuzfeldt-Jacob disease.

A similar disease called scrapie affects sheep.

Reseachers identified as the culprit an infectious protein, called a prion, contained in the nervous system of diseased cows. Prions are produced by both humans and cows. But sometimes they can become distorted - the scientific term is misfolded - and when they do, they can cause healthy prions to misfold too. The result is lack of coordination, mental decline and death.

But scientists have apparently cured a prion disease in mice.

Howard Federoff is a neurobiologist at the University of Rochester in New York.

"This study, in my estimation, illutrates the potential to now think about therapeutics development for this fatal neurogenerative disease," said Howard Federoff.

Investigators at the Medical Research Council in London infected 10-week old mice with misfolded prions that caused prion disease. Nine weeks later, they knocked-out the gene that causes the prions to infect other nervous system proteins. The mice quickly got better and were apparently cured, in contrast to another group of mice that had not been genetically altered.

The results of the study were published in the journal Neuron.

Observers caution the gene therapy was performed on newly infected animals and might not be effective in animals that have had prion disease for many months or years.

Nonetheless, Federoff is excited about the implications of the research.

"We may actually be able to significantly treat patients and alter natural history," he said. "That is very exciting."

Federoff says that might some day include drugs to cure non-infectious, prion diseases such as Parkinson's and Alzheimer's disease.