BSE: a decade on—part I

Abstract

Bovine spongiform encephalopathy (BSE), popularly known as "mad cow disease", was discovered in 1986 and has accounted for the deaths of over 165,000 cattle in the UK (by the end of January, 1997) with about 34,000 (mainly dairy) herds involved. The syndrome in the cow includes changes in posture and temperament, apprehension, and loss of coordination. There are many parallels with scraple in sheep, with similar neuropathological changes in the hindbrain that give it a spongiform appearance under the microscope. The facts have been broadly reviewed in The Lancet in 1990 and 1993, and in much more detail elsewhere. In a two-part article, the first of which appears here, we now summarise recent developments.

Impact of ‘Mad Cow Disease’ publicity on trends in meat and total vitamin A consumption in Geneva between 1993 and 2000

“…Shortly after that announcement a sudden and unexpected dietary change occurred throughout Europe. The publicity relating meat intake to the risk of developing a novel variant of CJD had a strong impact in Switzerland, which scored second (after the UK) in terms of BSE-affected cattle (300 out of the 1.2 million production cows; Collee & Bradley, 1997).…”

A Swiss population-based assessment of dietary habits before and after the March 1996 ‘mad cow disease’ crisis

“…The number of cows that died from BSE was about 160 000 from a cattle population of 11 million in the United Kingdom, but only about 300 from a cattle production of about 1.2 million in Switzerland, the country second most affected by the epidemic (Collee and Bradley, 1997).…”

Spread and Control of Prion Diseases in the Food and Feed Chains

“…[16,17] Significant changes in the manufacturing processes of feedstuffs that took place in the 1970s, including the introduction of mechanical systems that permitted continuous flow production and solvent extraction of fats, enabled PrP Sc to enter the livestock feed chain. [18,19] The recycling of animal by-products from BSE-infected animals caused a wide spread infection of BSE in cattle, [19] subsequently affecting the food chain through the consumption of the PrP Sc -contaminated meat products. [20] To date, more than 190,000 BSE cases have been reported in 28 countries since it was first identified in the UK in around 1986, [21] with approximately 97% of the cases being reported in the UK (Figure 1).…”