Scientists demand BSE tests for sheep

THOUSANDS OF sheep are to be tested for "mad cow" disease under recommendations to be considered by senior government advisers who are concerned about the possibility of BSE passing from cattle to sheep.

An intensive effort to try to assess the scale of the problem will be discussed at a meeting later this month of a committee of experts who have been given the responsibility of investigating the likely risk to human health.

Up to now only nine sheep out of an adult breeding flock of more than 20 million animals have been tested for BSE and scientists are worried that not enough is being done to see whether the disease was passed to sheep during the 1980s when they were fed the remains of BSE-infected cattle.

Scientists have known for some time that there is more than a theoretical risk of BSE infecting sheep. Experiments have shown that sheep fed on material from BSE-infected cattle can develop the disease and that although the symptoms are similar to scrapie - a natural disease of sheep - laboratory tests show the infective agent is identical to BSE.

The concern is that sheep farmers may not have noticed BSE in their flocks because it looks so much like scrapie, yet BSE is now known to be the cause of new-variant CJD in humans, which has so far affected 27 people.

The issue was raised yesterday by Professor Jeffrey Almond, of Reading University and a member of the Government's Spongiform Encephal-opathy Advisory Committee (Seac), who is to lead the investigation into the risk of BSE passing to sheep.

"I think there is a distinct possibility that BSE is out there in the sheep population ... I think if we found BSE in sheep it would be a national emergency and I think politicians would have to think very hard about what the appropriate response would be," he said.

The search for BSE in sheep has been hampered by the lack of a simple, cheap test to distinguish it from scrapie. At present the only test involves injecting pieces of sheep brain into different strains of laboratory mice to see whether they develop BSE - a process that can take two years or more.

However, Seac members believe it is time for the Government to spend what could amount to millions of pounds in testing several thousand adult sheep because of continuing concern that BSE in sheep may, like scrapie, be passed from one animal to another.

The plan would involve surveying a representative sample of adult sheep from across the country and sending brain material to the Neuropathogenesis Unit in Edinburgh, the Central Veterinary Laboratory in Weybridge or the Institute of Animal Health in Compton.

`National emergency', page 3