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Switzerland: Scientists Develop Test To Diagnose Mad Cow Disease

Scientists in Switzerland have announced progress in their efforts to develop a simple blood test to detect the presence of BSE -- commonly known as "mad cow disease" -- in cattle and Creutzfeldt-Jakob disease in humans. RFE/RL correspondent Jeremy Bransten spoke with Claudio Soto, the head of the team developing the new procedure at the Serono Pharmaceutical Research Institute, Europe's largest biotechnology company.

Prague, 14 June 2001 (RFE/RL) -- At present, the only way to know for certain if a cow has the brain-wasting disease BSE (for bovine spongiform encephalopathy) is to kill it and dissect its brain. Unfortunately, the same holds true for humans and the related Creutzfeldt-Jakob disease, or CJD.

This means that thousands of cattle are needlessly slaughtered on the mere suspicion of carrying the disease and human victims often live in physical and psychological agony, with no firm diagnosis. While there is currently no cure for the illness -- in either its cattle or human variant -- scientists see early detection, while the subject is still alive, as a first step in developing treatment.

Claudio Soto leads a team at Switzerland's Serono Pharmaceutical Research Institute, the largest biotechnology company in Europe. The team believes they have made a breakthrough in early detection with the development of a new blood test that they have successfully tested -- under laboratory conditions.

Current blood tests are unable to detect BSE or CJD because the level of abnormal prion proteins, the disease-causing agent, is too low. But Soto's scientists have developed a process which induces rapid prion replication in any given blood sample within a few hours, enabling detection. Soto explains:

"Prions are the infective agents in these diseases, and the difference is that they're a protein. They're not really a conventional infectious agent such as viruses or bacteria. So, there was no way to grow them in the lab. Now we have found a way, in which starting with a very, very small amount of the prions, we can grow them to a level that can be detected with any of the existent technologies."

More experiments will have to be conducted before the results can be certified and a commercially available blood test is developed. But Soto says his team's findings are a major breakthrough, especially because they advance scientists' knowledge of the disease's mechanism and thus might point the way to an eventual cure.

"This is not really one more test that has been developed. What we are trying here is to make a new concept in biology -- that proteins can be cyclically replicated. This will have an impact on diagnosis, as we discussed before, but also an important impact on understanding the biology of the disease and it will give us many clues to develop new therapies."

Soto says BSE and CJD share certain characteristics with Alzheimer's disease and Parkinson's disease, as well as other degenerative neural disorders. He believes his findings could advance efforts to find cures for those ailments.

"Creutzfeld-Jacobs disease, mad cow disease, and all the prion-related disorders belong to a larger group of diseases that have in common the same mechanism. And the mechanism is that the normal proteins that we all have in the body, under certain conditions, change their shape and acquire a toxic form that start killing the cells in the body. And this mechanism is shared by several other diseases, including Alzheimer's, Parkinson's disease, and several others."

Like BSE and CJD, Alzheimer's and Parkinson's are difficult to diagnose and doctors have to rely on clinical symptoms, which often do not manifest themselves until the disease has progressed.

"In these diseases, the diagnosis is mainly clinical -- by the symptoms. But this is only done relatively late, when the symptoms are already obvious. The problem with that is that as soon as we have a therapy, clinical diagnosis will not be sufficient, because we will take the patient already in a late stage of the disease. What we would like from the therapeutic point of view is to take them earlier, to diagnose them earlier, before the damage in the brain is done."

The full details of the Soto team's research can be found in the latest issue of the British scientific journal "Nature."