Posted on 12/25/2003 1:28:53 PM PST by Pubbie
Mad cow disease strikes fear into the hearts of meat lovers everywhere, and with good reason. Although slightly more than 100 deaths have been attributed to eating contaminated beef, some researchers speculate that millions of people may one day fall victim to the fatal human form of the disease as a result of eating a single tainted burger or steak.
But provocative new research questions the link between infection in cattle and that in humans. Writing in the Oct. 13 issue of the British Medical Journal, Scottish epidemiologist George Venters, MD, of NHS Lanarkshire, argues that there is no clear evidence to prove that mad cow disease can be transmitted to humans by ingesting contaminated meat products. He adds that the case for such transmission is weak.
"This will undoubtedly be controversial within the scientific community, but that is part of the point," Venters tells WebMD. "I want to prompt more appropriate explanations about what is going on here than the facile one of infection. The infectivity hypothesis is, in fact, becoming a bit threadbare."
Mad cow disease, known medically as bovine spongiform encephalopathy (BSE), was first identified among British cattle in 1986 and has since spread throughout Europe. Since the mid 1990s, scientists have become increasingly convinced that a recently identified, rapidly degenerative, fatal brain disease in humans called new variant Creutzfeldt-Jakob disease (CJD) is caused by eating the meat of infected cattle.
Venters says there may be nothing new about new variant CJD. He suggests the cases classified as such may actually have been classical CJD, which is not a food-borne illness at all.
"If you have a food-borne infection, you expect the number of cases to rise at the same rate as the population was exposed to the infection," Venters says. "That has not happened here. People try to explain this by saying there may be a long incubation period, but the fact is that you have had cases occurring for seven or eight years now and the numbers have not been increasing."
Venters calls new variant CJD "the epidemic that never was," because its numbers have not increased dramatically in the years since it was identified. Using established research methods, Venters says he could find no direct evidence that the infectious proteins known as prions, which cause BSE in cattle, are infectious to humans.
"It is unlikely that human beings who eat prions from other species are likely to get infected, because our own defenses are well enough organized to digest or to destroy these prions," he says.
But prion researcher Robert B. Petersen, PhD, disagrees and says while some of Venters' assumptions may seem valid on paper, they just don't reflect what is going on. Petersen says studies have shown that the molecular signatures of BSE and new variant CJD are virtually identical. And animal studies have confirmed the pathological similarities of the two diseases. Petersen is an associate professor of pathology at Cleveland's Case Western Reserve University and is chief scientific officer for a company working to develop a diagnostic test for BSE.
Petersen tells WebMD that by looking at all the features of the disease, it's clear that there are different types of CJD. The new variant CJD doesn't appear to be like anything that occurred before doctors started to study BSE.
People may argue that by now, doctors should be seeing more people sick with variant CJD, Petersen says. But in order to make such an assumption, scientists have to know a lot more about the disease than they do today, such as how long it takes to show signs of the disease after becoming exposed to it. That period of time could be anywhere from 10 to 60 years, Petersen says. "We just don't know at this point."
Similarly, there is no way to know whether an epidemic of new variant CJD will occur in years to come among people who may have already been infected, he says.
Jeeeez.....P. T. Barnum was right.
This is NOT a new problem. Much sequencing has been done. 72 of 72 vCJD patients are homozygous for M at position 129. vCJD is caused by bovine prions.
Assay is too short. vCJD transmitted by transfusion. Prions in blood. Blood in muscle cuts.
Another dopey non sequitur. Are you guys a tag team?
I have provided links to the data. This is NOT a new problem to those in the field and the data are quite clear. Don't know your background, but it doesn't sound like you have any familiarity with the science side.
Try looking at the data, which are pretty straightforward.
No, don't know him/her...don't necessarily agree. Would you just answer my question? I'm trying to figure out what you mean.
Okay. I'll take you at your word.
Huh? Would YOU eat BSE contaminated meat?
BSE has been found in the brain and spinal chord of infected animals....not in the muscles, ie. the meat.
I asked for your credentials as you come on here new to the site just in time for this "crisis," am I wrong to request this?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.