HL Deb 11 April 2002 vol 633 cc123-4WA
The Countess of Mar

asked Her Majesty's Government:

How ovine genotypes susceptible to scrapie can be identified with accuracy. [HL3663]

Lord Whitty

Susceptibility to scrapie is known to be linked to variations in the amino acids encoded at three sites (codons)—136, 154 and 171—on the sheep PrP gene. The available testing technologies use DNA sequencing to identify those variations. In connection with the national scrapie plan, the Government have awarded contracts to two laboratories to install and operate automated genotyping facilities. A blood sample is taken from the sheep, which is identified by an electronic transponder linked by barcode to the blood sample tube. Internal and external quality controls operate at the laboratories.

The Countess of Mar

asked Her Majesty's Government:

What scientific advice they have received about alternative methods for eliminating scrapie other than widespread slaughter such as the identification of high-immune response animals for breeding programmes. [HL3664]

Lord Whitty

In line with scientific advice, the Government last year launched the national scrapie plan for Great Britain, whose objective is to eradicate scrapie by breeding genetic resistance to transmissible spongiform encephalopathies into the sheep flock. Participation in the plan is voluntary and it does not involve the widespread slaughter of sheep. The plan only requires participants to remove from the breeding flock (either by slaughter or castration) those rams with the genotypes that are the most susceptible to scrapie. So far the proportion of rams falling into this category has been relatively small (about 8 per cent). Where the requirement to remove from the breeding flock causes problems, veterinary advice is available and in exceptional situations appeals can be considered. Experience in other countries indicates that a policy based solely on widespread slaughter is unlikely to be effective in the long term in eradicating scrapie. The available scientific information suggests that scrapie does not promote a detectable immune response in the host. Development of laboratory tests which can identify animals incubating the disease is in progress but a practical technique is not yet available.