November 19, 2002 The Guardian (London) by James Meikle
Plans to protect Britain's 40 million sheep from BSE-like diseases
have suffered a potentially serious setback
after a sheep supposedly resistant to such conditions was
reported to have been infected in a laboratory test.
The sheep succumbed more than 33 months after being injected in the brain with brain material from a BSE-contaminated cow. Further tests are being done to confirm the diagnosis, but it appears the first time such disease has been caused, albeit artificially, in a sheep of this type. Others with less genetic resistance have succumbed far more rapidly. Government agencies yesterday insisted that lamb and mutton could still be eaten safely by consumers, since the risk of infection happening naturally in breeding or food flocks remained theoretical.
Resistant sheep fed BSE-infected brain, rather than having it injected, had not succumbed to the disease, even though some with low genetic resistance had shown signs of BSE within four months.
Nevertheless, the long-term national programme to force farmers to replace stock with inbred resistance to these diseases within 10 years could be undermined if further cases occured.
So far about a fifth of British sheep are resistant to a BSE-like disease called scrapie, which is thought to affect about 10,000 sheep a year but has never been known to be harmful to man.
The government hopes to quickly make more than eight in 10 lambs and sheep genetically resistant, in the belief they will also be resistant to BSE, which most scientists now accept did transfer to humans through their food. It has allocated pounds 120m to the first three years of the programme.
The French government may be tempted by the news to step up its attempts to make all EU countries, including Britain, follow its example and from January remove more potentially infected material from sheep as a precaution in case BSE is ever found in flocks in the field. The experiment that uncovered the uncomfortable result is being conducted at the Institute of Animal Health in Compton, Berkshire, for the Department of the Environment. The sheep was one of 19 resistant to scrapie which had been imported from New Zealand, a country free from the disease.
Elliot Morley, the animal health minister, tried to reassure the public and farmers yesterday. "It has been known for some time that sheep can be infected with BSE under experimental conditions. So this result, if confirmed, will tell us nothing more than we already know about the possibility of BSE in the national flock. All it has done is confirm the theoretical risk of BSE remains. There is no reason people should not buy any sheep meat. Nothing has changed in that."
It would still be important for farmers that scrapie itself was bred out of their sheep, whether or not that brought benefits in BSE protection, Mr Morley said.
He revealed that the one resistant sheep that succumbed had taken nearly twice as long as the average 18 1/2 months in which sheep more susceptible to scrapie had become infected. Seventeen of 19 injected in this group had developed BSE. In addition, sheep with little resistance had gone down with BSE after being fed infected brain.