17 Feb 11 The BSE epidemic is finally over
The first hint of catastrophe came a quarter of a century ago. In October 1987, David Brown of The Sunday Telegraph described “a mystery brain disease [which] is killing Britain’s dairy cows and vets have no cure”. A few months later, he disclosed that the government had launched an inquiry into what was now being called bovine spongiform encephalopathy, or BSE. By the end of the decade, his stories were referring routinely to “mad cow disease”, and a chilling new phrase had entered the language.
The BSE epidemic cost us billions, and devastated the British farming industry. Now, that plague is at an end. A few days ago, in New Scientist, we described how just 17 cases were recorded worldwide in cattle last year.
Brown, who died in 2001, aged just 54, would have been surprised by the lack of publicity given to BSE’s demise. Overall, as many as three million animals were infected; in the peak year, 1992, the UK saw 37,280 diagnoses. Yet there are good reasons why any celebrations have been put on hold. All told, around half a million infected animals entered the food chain. Although it remains unclear how many people ate the most infectious parts, it is clear that the majority of the British population was exposed.
So far, the human equivalent of BSE, variant Creutzfeldt-Jakob disease (vCJD), has claimed 170 lives, mainly through consumption of BSE-infected beef. And because of the extraordinary incubation time of the disease, it is possible that many more cases may be waiting in the wings.
The story of BSE starts in the 1960s, with two London-based researchers – Tikvah Alper, of Hammersmith Hospital, and John Stanley Griffith, of Bedford College – who were studying scrapie, the equivalent disease in sheep. They suggested that such “spongiform” brain disorders were caused not by conventional agents such as viruses and bacteria, but a novel type of infectious agent: a rogue protein….