UK report urges screening for ‘‘mad sheep’’ disease

The United Kingdom’s Food Standards Agency has called for urgent development of new ways of detecting whether mad cow disease, or bovine spongiform encephalopathy (BSE), has spread to sheep.

In a report on anti-BSE measures in the United Kingdom, the agency warns that current research is too slow and says that if BSE is found in the 40 million-strong national sheep flock, existing controls would have to be revised.

There has been growing concern that some of the 4000 sheep who die of scrapie each year in the UK may have been suffering from BSE, which was first identified as a neurological disease of cattle in 1986. In 1996, the UK’s Spongiform Encephalopathy Advisory Committee reported that scientists had successfully infected sheep by feeding them with infected brain tissue.

‘‘The current research to look for BSE in sheep is costly and slow,’’ says the report. ‘‘As a matter of great urgency, there is a need to develop and apply a rapid screening method so that large numbers of sheep can be tested to reduce the uncertainty of whether or not BSE occurs.’’ The report also urges a complete ban on intra-species recycling of blood, gelatine and tallow in animal feed, as well as checks on sheep intestines used for sausage casings to ensure that the processing removes lymphoid tissue. The possibility that some cattle and sheep may be carriers of BSE without developing the disease has also to be looked into. There are fears that if BSE is found, slaughtering of affected sheep flocks may have to be considered.

The move by the agency comes hot on the heels of publication of the report of an official enquiry into the BSE crisis in the UK. The report says that putting animal protein in cattle feed was ‘‘a recipe for disaster’’ and that the government at the time was preoccupied with preventing an alarmist over-reaction to BSE. The report of the enquiry, which took two years and cost almost £30 million (US$ 42 700) to produce, said there were bureaucratic delays in responding to scientific warnings about the risks, but no deliberate intention to deceive.

Up to early November this year, variant Creutzfeld-Jakob disease (vCJD), the human form of BSE, has killed at least 80 people in the United Kingdom, 3 in France and 1 in the Republic of Ireland. More cases are expected, especially in the United Kingdom, where the government has now agreed to compensate vCJD sufferers and their families.

In France, a nationwide scare over BSE was triggered in October by potentially infected meat finding its way onto the shelves of three supermarkets. In mid-November the government responded to public fears by mandating compulsory random testing of all herds and banning the use of meat and bone meal in animal feed. The government is now facing court action by the families of two victims of vCJD demanding compensation. Sales of meat in France have fallen by 40%.

In a further blow to French cattle farmers, on 17 November, Italy banned imports of French cattle more than 18 months old and of French beef on the bone. Similar bans of French meat imports have been announced by Austria, Brazil, Greece, Hungary, Poland, Portugal, Russia, Spain and Switzerland, according to press reports. The Italian government has also banned the use of meat and bone meal in animal feed for herbivorous animals and has plans to screen all cattle more than two years old for BSE. In doing so, it is complying with a 1994 European Union decision to prohibit the feeding of mammalian protein to ruminants throughout the Union.

Roger Dobson, Abergaveny

World Health Organization Genebra - Genebra - Switzerland
E-mail: bulletin@who.int