BSE arose in Britain during the mid-1980s, apparently jump-started by the cannibalistic practice of feeding cows protein supplements made from dead cows. BSE appears naturally in very rare cases. The disease was amplified when brain tissue from naturally infected cows was processed and fed to thousands of other beasts. (Some scientists still favor another, earlier theory: that BSE was caused when scrapie, a BSE-like illness in sheep, jumped the species barrier after cows were fed supplements made from dead sheep.) The British government denied for a decade that BSE endangered human health, but when young people started dying from nvCJD in 1995, Britons went bonkers, savaging the Tory government and public health officials (correctly) for their laxity. Britain has slaughtered millions of cows and cleaned up slaughtering and rendering practices in a mostly successful effort to suppress the disease. The number of bovine cases dropped from tens of thousands per year to about 1,000.

But BSE seems to have infiltrated the continent because of British foul play. Britain exported cannibal cow feed during the '90s—even after banning the feed at home. Still, the number of cases on the continent remains tiny compared to the U.K. epidemic: No European nation has found even 1,000 mad cows; Great Britain has had 180,000.