An MD&DI March 1999 Column
How Now, Mad Cow?
Strong Measures to Forestall a Potential Killer
Taking a hard look at the past, the British government enacts extraordinary policies to combat what is still a hypothetical risk.
One of the unusual and ominous characteristics of the last twenty-five years or so of medical history has been the emergence of new and devastating infectious diseases. These have spawned a series of crises ranging from the deadly but relatively circumscribed Ebola fever outbreak of the mid-1970s to the monumental and ongoing disaster of the AIDS pandemic.
The most recent episode, in 1996, involved the eruption of "mad-cow disease"or bovine spongiform encephalopathyamong livestock in Great Britain, and the probable transmission of the infectious agent to 31 people. "Probable" because there remains little definitive knowledge about the origin of the malady, the manner in which it spreads, or the source or extent of the contagion in humans, where it is known as "new-variant Creutzfeldt-Jakob disease."
Despite these uncertainties, recent research suggests the possibility that the uniformly fatal disorder could be transmitted through transfusions of certain blood components from unknowing carriers. With no screening test available, this threat has prompted the British government to undertake the costly and unprecedented step of destroying nearly all of the plasma and white cells from the country's entire blood supply in an effort to cut the risk of future infection. The plasmathe protein-containing, fluid portion of the blood used in the manufacture of various blood productswill be replaced with plasma from the United States, where the disease has not been reported.
If all of this sounds familiar, it is because the scenario is eerily reminiscent of the situation that existed in the early years of the AIDS crisis, when the topic of debate was the safety of the U.S. blood supply. The difference is that the British seem to have learned from our mistakes, and prefer erring on the side of caution as opposed to erring on the side of a reckless disregard for the lives of thousands of potential victims.
Whether we have learned from those same mistakes is open to question. Judging by his published commentsthat the British response, "based on a theoretical risk only," is thus "a bit extreme"the chief medical officer of the American Red Cross appears particularly oblivious, given the lamentable role of the Red Cross and the rest of the U.S. blood-banking industry during the early 1980s, when mounting evidence that AIDS could be transmitted through blood was similarly termed an overreaction.
As in every significant medical emergency, the "mad-cow" phenomenon has resulted in commercial ramifications involving the device industry. Companies supplying bovine- or other animal-derived products have been forced to reevaluate the safety of their materials and institute stringent source control and validated methods for eliminating or inactivating transmissable agents. Other firms stand to benefit, especially those equipped to provide the white-cell filtration, or "leucocyte reduction." This procedure apparently enhances transfusion safety in a variety of ways, including the removal of numerous blood-borne viruses and bacteria, and is under consideration by FDA for more generalized adoption.
Determining whether the extraordinary preventive measures implemented in Britain are finally a waste of time and moneyas is fervently hopedwill take a number of years, since new-variant CJD remains dormant for long periods. Viewed as a disbursement of moral capital, however, the soundness of the actions seems beyond reproach.