Mad Cow Disease From Blood Transfusion
An Isolated Case -- or the Beginning of a New Epidemic?
Mad Cows, Beef, and Blood continued...
Nearly 200,000 British cows are thought to have been mad cow disease carriers. As of last December, there were 153 human cases. Just today, British researchers reported that the annual number of cases seems to have reached a peak and is now dropping off -- or at least reaching a plateau of about 15 new cases per year.
That could change if the blood supply is tainted. But it's not likely, says James P. AuBuchon, MD, chair of the pathology department at Dartmouth Hitchcock Medical Center in New Hampshire, and a spokesman for the American Association of Blood Banks.
"Transfusion must not be a very effective way of transmitting vCJD, or we would have seen many more cases by now," AuBuchon tells WebMD. "This is not something like hepatitis, that is easily spread. But we will do what we can to reduce the risk."
In response to public demand for action, U.K. blood centers are filtering white blood cells out of donated blood. But the experts who spoke with WebMD say this step is based on public relations, not on science. AuBuchon and Cashman agree that there's no evidence removing white blood cells makes blood transfusions safer.
Mad cow disease -- vCJD -- is caused by a weird protein, not a living germ. This kind of protein -- known as a prion -- has the bizarre ability to transform normal brain proteins into new prions. Eventually, this process clogs up the nervous system.
There's no treatment, and no simple test for the mad cow prion. Cashman and others are working to develop diagnostic tests. And Cashman's team is getting ready to test a new vCJD vaccine in mice.