§ Mr. BakerTo ask the Secretary of State for Health if he will set out his Department's assessment of the hierarchy, by method of transmission, of likelihood of risk of transmission of BSE. [111897]
§ Yvette Cooper[holding answer 1 March 2000]: In experiments involving strains of prion that have been adapted to laboratory animals, such as mice, it has been shown that intracerebral inoculation is more likely to cause infection than intravenous injection which, in turn, is more likely to cause infection than intra-peritoneal or sub-cutaneous inoculation. Parenteral exposure is, in turn, more likely to cause infection than oral exposure.
Experiments on mice challenged with a strain of scrapie—a Transmissible Spongiform Encephalopathy of sheep—that had been adapted to mice showed that exposure by placing the inoculum directly into the stomach was about 100,000 fold less efficient than by direct inoculation into the brain.
As part of its remit to consider emerging scientific findings the Spongiform Encephalopathy Advisory Committee (SEAC), the expert Committee that advises the Government on all aspects of TSEs, has considered 787W the results of experiments designed to investigate the link between BSE and variant CJD (vCJD). The Committee has stated that
BSE and vCJD were caused by a closely similar prion strain, and concluded that vCJD was an acquired prion disease caused by exposure to BSE or BSE like agent.However, these results do not provide information about the route of exposure, and research to establish this factor remains part of the Government's TSE Research Strategy.