THE BSE RISK: To eat or not to eat - the facts behind the disease

KEY QUESTIONS

What is BSE?

BSE, which stands for "bovine spongiform encephalopathy", is also known as "mad-cow disease". It is a degenerative disease of the brain found in cows, leading to disorientation followed by dementia and death. Its first recorded occurrence was on a British farm in Ashford, in 1985.

How and when did it start?

Scientists are still uncertain whether it started from feeding cattle with the remains of sheep infected with "scrapie" (the equivalent of BSE), or if it arose spontaneously in cows.

What is CJD?

Creutzfeldt-Jakob Disease is a rare degenerative disease in humans which leaves sponge-like holes in the brain, just as BSE does in cows. The early signs are confusion, followed by a rapid descent into dementia. There is no treatment and it is always fatal.

Why is there such concern about CJD now?

In the past, CJD only seemed to affect people very late in life, but over the past three years there have been a number of cases in Britain involving CJD in both teenagers and dairy farmers, which stretched coincidence to its limits.

How are BSE and CJD connected?

Both diseases seem to be caused by changes in a cell- membrane protein known as a "prion". Although BSE can be passed between cattle, until yesterday the Government had always denied that eating BSE-infected beef could cause CJD.

How much British beef is infected?

The number of cattle with BSE has fallen since hitting a peak in 1992, but some scientists estimate that thousands of cattle in the early stages of the disease slip through checks before slaughter and enter the food chain.

How many cases of BSE are there annually? How many of CJD?

The number of cases of BSE appears to be falling, while those of CJD - which on average affects about one per million population in most countries - has recently risen, though not beyond statistical variation.

What steps has the Government taken to minimise the risk to humans and other species?

In July 1988 the Government banned the use of sheep and cow remains for farm feeds. In 1989 it banned the use for human consumption of "specified bovine offals" (SBOs), including the brain, spinal cord, spleen, tonsils and intestines of all cattle over six months old. These were the parts judged most dangerous to eat because of the likelihood of the BSE agent being concentrated there.

Can any other species get it?

Yes. BSE can be passed to a wide range of animals, including mice, cats, pigs, sheep and goats. However, in some cases it can only be passed by injecting infected material into the animals' brains.

Is it safe to eat veal?

Opinion is divided on whether veal calves incubate the disease, and whether they could pose any risk to humans; but SBOs are not removed from veal.

Does BSE affect milk?

It is not thought to, because the prion protein is not found in milk.