Mad Cow Disease From Blood Transfusion
An Isolated Case -- or the Beginning of a New Epidemic?
Feb. 5, 2004 -- It could be an isolated case, or it could be the beginning of a new wave of human deaths from mad cow disease.
A British man who died of mad cow disease likely got it from a blood transfusion, U.K. authorities confirm. The report appears in the Feb. 7 issue of The Lancet.
Charlotte Llewelyn, PhD, of the U.K. National Blood Service, Cambridge, and colleagues note that a 62-year-old man came down with mad cow disease -- more properly, variant Creutzfeldt-Jakob disease of vCJD -- six and a half years after getting a blood transfusion.
The transfusion was traced to a person who donated the blood three years before developing symptoms of mad cow disease. There's no definitive proof the transfusion actually carried the poisonous protein that causes vCJD. But Llewelyn and colleagues say there's only one chance in 15,000 to 30,000 that the man got the disease some other way.
This worries Neil Cashman, MD, of the center for research in neurodegenerative diseases at the University of Toronto. Cashman is a leading researcher in the quest to find a test -- and possibly a vaccine -- for vCJD.
"This is something new," Cashman tells WebMD. "A single case doesn't mean anything. It could be a red herring -- but it could be the beginning of an epidemic of blood borne transmission of this disease. Many of the authorities, including myself, are very concerned."
Mad Cows, Beef, and Blood
Why the worry about a single case? After all, Llewelyn's team found 48 people who'd received blood transfusions from 15 different people that later came down with vCJD. There's no test that can tell whether a person is carrying the mad-cow protein. But none of the transfusion recipients had any sign of the disease.
"The disease has an incubation period of 10 years plus, and it has not been 10 years since the disease was first described," Cashman says. "Now, seven years after the description of vCJD, we have a case that looks like probable transmission by blood transfusion. Much as I would love to say it's not going to be a problem, I am worried there will be a secondary epidemic of transmission through blood and blood products."
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.