bovine spongiform encephalopathy

Disease of cattle, related to scrapie in sheep, that attacks the nervous system, causing aggression, lack of coordination, and collapse. It was formally identified in the UK in November 1986, and between 1986 and 2002 there were 181,376 cases of BSE identified in British cattle, which were all slaughtered to contain the spread of the disease. After safety measures were put in place for the selection and processing of cattle, British beef was declared safe (by the UK government) in 1999. Following outbreaks of BSE in French, German, and Spanish cattle in late 2000, European Union (EU) agriculture ministers agreed to ban, as of 1 January 2001, the use of meat-and-bone meal from animal feed and to ban all cattle over 30 months old from the food chain unless tested for BSE.

BSE is one of a group of diseases known as the transmissible spongiform encephalopathies, since they are characterized by the appearance of spongy changes in brain tissue. Some scientists believe that all these conditions, including Creutzfeldt-Jakob disease (CJD) in humans, are in effect the same disease, and in 1996 a link was established between the deaths of 10 young people from CJD and the consumption of beef products.

The cause of these universally fatal diseases is not fully understood, but they may be the result of a rogue protein called a prion. A prion may be inborn or it may be transmitted in contaminated tissue.

Controversy in Europe Despite safeguards against infected meat and the scientific and legal acceptance of British beef by the rest of the EU, France refused to lift its illegal embargo on British beef, claiming that there was still a risk of infection of CJD for humans. The question of British beef had gained political significance by the end of 1999, as the British prime minister Tony Blair pointed out at an EU summit in Helsinki, Finland, that France was contravening European law and threatened to sue the French government for millions of pounds on behalf of British farmers.

BSE in Europe In September 1996, the Swiss government ordered the slaughter of up to 230,000 cattle. Switzerland trailed only Britain in the number of known cases of BSE. The EU banned beef exports from Portugal in November 1998 after a number of BSE cases were revealed. 500 cases were reported by January 2001, when the country instituted a cattle slaughter program. In 2000 scientific advisers to the European Commission concluded after a two-year study that Germany, Italy, and Spain were also likely to have cases of BSE infection. The first case of BSE in Denmark was reported in March 2000, the first in France in October, and the first in Germany and Spain in November. In January 2001, the first cases of BSE were reported in Italy. The same month, the German government ordered the destruction of 400,000 cattle. The mass slaughter was part of European Union measures against BSE, but provoked outrage in Germany, where it was widely seen as a way to help farmers rather than protect consumers.

BSE in Asia Asia's first case of BSE as reported in mid-September 2001 on a farm in Chiba, near Tokyo, Japan. China, South Korea, and Malaysia immediately banned the import of Japanese beef.

BSE in North America Throughout the outbreak of BSE in Europe, the USA maintained that its cattle herds were free of the disease. However the first case of vCJD was reported in Canada in August 2002 and the first case of BSE in the USA itself was reported in December 2003. Although the scale of the problem was initially downplayed, by March 2004 the US government had authorized the testing of up to 500,000 cattle.