March 21, 2002 Wisconsin State Journal by Ron SeelyScientists are generally very restrained when it comes to talking about the potential health impacts of research findings. They are adept at hedging, at cushioning their conclusions with qualifiers.
So it is striking to hear researchers talk about chronic wasting disease, or CWD, and to hear the worry in their words. The geographic leap CWD made from South Dakota to reach Wisconsin has researchers, who know little about how the disease spreads, especially frustrated.
"I was really disappointed to hear about the findings in Wisconsin," said Beth Williams, a Wyoming veterinarian and researcher who has studied the disease for years.
"That's a large geographic movement and into a very dense population of whitetails. I'm afraid that might be quite a problem."
Of special concern are the latest research findings on CWD. Scientists at the University of California-San Francisco have found the infectious proteins that cause the disease in the muscle tissue of lab mice.
Until now, researchers had believed the proteins, called prions, occur mostly in nerve tissue, including the brain and spinal cord, and to a lesser extent in the eyes, tonsils and lymph nodes.
So far, there have been no cases of CWD spreading to humans in the form of Creutzfeld-Jakob disease or to livestock as mad cow disease, both of which are part of the same family of prion diseases called transmissible spongiform encephaalopathies.
But mad cow disease has jumped the species barrier, so far killing 116 people in Europe.
Even though there haven't been cases of CWD spreading to people, the DNR has warned Wisconsin residents to avoid eating the parts of deer where the prions were thought to accumulate, the nerve tissues mentioned above.
Muscle tissue should pose little threat, researchers indicated, because prions aren't usually found in these tissues.
But the California research may now require revising even this recommendation. So it is as science races - if science can ever be said to race - to keep up with a breaking and perplexing news story.
Of course, we're talking about mice muscles here and scientists warn they aren't sure if the research applies to deer and livestock. Also, the prions found in the research mice were in lower concentrations than the malformed prions found in the brains of diseased animals.
As a result, Patrick Bosque, assistant professor of neurology at the University of California, warned against overstating his findings.
Similarly, Mike Miller, wildlife veterinarian for the Colorado Division of Wildlife, said the implications for deer and livestock are unclear and added he would be talking with Bosque about how to proceed in his state where wild and captive herds of elk and deer have the disease.
There is some good news here. While the presence of prions in mouse muscle tissue may have some unsettling implications, it may also provide hope for a much simpler test to detect the disease in animals.
Currently, an animal suspected of having the disease must be killed and samples from the brain stem have to be studied in the laboratory, a days-long process.
If scientists learn how to detect the diseased prions in muscles, however, they may be able to devise a simple biopsy of muscle tissue to diagnose the disease.
That would go a long way toward making it easier to fight the spread of the disease.