The "mad cow" disease diagnosed in a U.S. cow has set off a new round of predictable, but groundless, panic.
Foreign governments promptly banned imports of U.S. beef. Investors dumped the stocks of beef- related companies. And, of course, what health scare would be complete without hyperventilating calls for even more government oversight of an already highly regulated industry?
There's no question that bovine spongiform encephalopathy, or BSE -- commonly called mad cow disease -- is a neurological disease in cattle. But the notion that people can contract a human form of mad cow by eating beef from infected cattle is more bun than burger.
The first epidemic of mad cow broke out among cattle in Britain in 1986. Eight years later, human cases of a supposedly novel brain ailment, called new variant Creutzfeldt-Jakob disease, or variant CJD, began appearing in Britain.
Though laboratory testing seemed to indicate that BSE and variant CJD were similar, no one could determine with certainty whether and how the BSE epidemic was related to the "human mad cow" cases.
There were no geographic areas in Britain with a significantly higher incidence of variant CJD cases, and there were no cases of variant CJD among apparently high-risk groups such as farmers, slaughterhouse workers and butchers.
When researchers considered the possibility that variant Creutzfeldt-Jakob disease was caused by consumption of beef from BSE-infected cattle, no correlations could be established between variant CJD and any specific meat or dairy product. No one could even establish whether any of the variant CJD victims ever consumed beef from diseased cattle.
Some researchers nevertheless became fixated on the idea that consumption of infected beef was the culprit behind variant Creutzfeldt-Jakob, especially after it was discovered that 1980s slaughterhouse and meat preparation practices inadvertently might have allowed tissue from diseased cattle to be mixed into packaged meat products such as hot dogs, sausages, beef patties, luncheon meat and the like.
That mere hypothetical possibility spawned mad cow mania.
But the infected-beef hypothesis doesn't explain why variant CJD tends to occur in young people; most cases have occurred among 15- to 25-year-olds. And it doesn't offer the slightest clue as to why only about 130 variant CJD cases have occurred in a British population of 60 million people who are exposed to millions of pounds of potentially contaminated beef products.
