New mad cow strain found

A new form of mad cow disease has been found in Italy, according to a study released yesterday, and scientists believe that it may be the cause of some cases of human brain-wasting disease.

While the strain has been found in only two Italian cows, both apparently healthy, scientists in Europe and the United States said the discovery should provide new impetus for the Department of Agriculture to adopt the more sensitive rapid tests used in Europe because it may not show up in those used here.

Reports of unusual types of mad cow disease have also been reported recently in France and Japan. Scientists say the new forms suggest that many cases of "sporadic" human disease -- by far the most common kind, responsible for about 300 deaths a year in the United States -- are not spontaneous at all, but come from eating animals.

The brain-destroying diseases involve prions -- misfolded proteins that are believed somehow to induce other proteins to fold incorrectly, leaving patches of useless debris and holes.

The study, by a team from universities in Turin, Verona, Brescia and Milan, was edited by Dr. Stanley Prusiner, who won a 1997 Nobel Prize for his prion work. Results of the recent study appear this week in The Proceedings of the National Academy of Sciences....