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From: TSS ()
1 © SEAC 2006 SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE Draft minutes of the open session of the 92nd meeting held on 28th April 2006 Royal Horticultural Halls and Conference Centre Greycoat Street London SW1P 2QD Members: Professor C. Higgins (Chair) Mr. J. Bassett Professor D. Brown Professor N. Hooper Mr. P. Jinman (Deputy Chair) Professor C. Lasmézas Professor J. Manson Professor G. Medley Dr. P. Rudge Professor A. Williams Assessors: Dr. P. Christie (SE) Dr. A. Douglas (DARDNI) Dr. A. Gleadle (FSA) Mrs. E. Lawrence (DH) Dr. M. Simmons (NAW) Technical Experts: Dr. P. Barrowman (Defra) Dr. P. Bennett (DH) Mr. P. Burke (Defra) Professor N. Gill (HPA) Dr. I. Hill (FSA) Dr. D. Matthews (VLA) Dr. J. Stephenson (DH) SEAC Secretary: Miss K. Richards Secretariat: Dr. T. Barlow Dr. D. Cutts Dr. N. Ebenezer 2 © SEAC 2006 Dr. P. Keep Dr. C. Ravirajan 3 © SEAC 2006 ITEM 1 – CHAIR’S INTRODUCTION 1. The Chair welcomed everyone to the 92nd meeting of SEAC. 2. The Chair announced that Professor Alun Williams had joined SEAC to replace Professor McConnell who left the committee last year. Professor Williams is Head of Department of Veterinary Pathology and Infectious Diseases at the Royal Veterinary College and leads the European Union (EU) STOPPrions project. Mr Peter Jinman has been reappointed to SEAC following an open recruitment exercise and has also been reappointed Deputy Chair. 3. The SEAC Secretary explained that open meetings allow the public an opportunity to observe the committee at work and provide an insight into how an advisory committee provides independent scientific advice to Government. Government officials responsible for transmissible spongiform encephalopathy (TSE) policy are present and may be invited to contribute to discussions. 4. The committee will hold a reserved business session in the afternoon to allow discussion of unpublished scientific data relating to TSE infectivity in blood. This is in accordance with the SEAC Code of Practice. Short summaries of the open and reserved business discussions will be posted on the SEAC website next week. A list of website addresses of recently published reports relevant to TSEs has been tabled. 5. The next meeting will be held on Thursday 6th July 2006 at the Royal Horticultural Halls and Conference Centre in Westminster, London. 6. Apologies for absence have been received from Dr Jackie Chambers, Ms Diane McCrea, Professors James Nicoll and Margaret Stanley. 7. Members were reminded that they are obliged to declare any commercial or other interests they may have at the start of the relevant agenda items. They were also reminded of the obligation to notify the Secretariat of any changes to the register of members’ interests as soon as they occur. 4 © SEAC 2006 ITEM 2 – APPROVAL OF MINUTES FROM SEAC 91 (SEAC 92/1) AND MATTERS ARISING 8. The minutes were agreed as a correct record1. ITEM 3 - CURRENT ISSUES 9. SEAC was informed about the following issues: • Publication of a paper by Ironside et al.2 reporting the valine homozygous genotype of two of the three appendix samples found to be positive for the presence of abnormal prion protein (PrPSc) by Hilton et al. (2004)3. The third appendix could not be genotyped. The finding that both samples which could be genotyped were valine homozygous has implications for the predicted prevalence of vCJD infectivity in the UK population. SEAC had considered these data at SEAC 84. • Publication of a paper by Andreoletti et al.4 reporting that PrPSc was found in the spleen of an ARR homozygous sheep ten months after oral challenge with BSE. Dr Danny Matthews (Veterinary Laboratories Agency [VLA]) noted that the animals had been challenged with a very high dose of BSE at less than a week old in this study. • Following the agreement of the Chief Medical Officer, the Department of Health (DH) had requested that the Health Protection Agency (HPA) convene an expert group to consider the SEAC recommendation5 for testing of post mortem tissues to ascertain better the prevalence of vCJD infection in the UK. Professor Noel Gill (HPA) explained that the HPA is actively engaged in convening this group. SEAC would be asked to comment on the remit and membership of the group, probably by the end of May 2006. It was noted that DH has agreed to continue funding the tissue collection phase 1 Note added after SEAC 92. In paragraph 9, third bullet point “A paper on the case is being prepared by the Transfusion Medicine Epidemiology Review.” was changed to “A paper on the case is being prepared by the National Prion Clinic.” and in paragraph 25 “…sonicated microsomal fractions. Biochemical assays and hamster bioassay.” was changed to “…sonicated microsomal fractions by biochemical assays and hamster bioassay.” 2 Ironside et al. (2006) Variant Creutzfeldt-Jakob disease: prion protein genotype analysis of positive appendix tissue samples from a retrospective prevalence study. BMJ Online. 3 Hilton et al. Prevalence of lymphoreticular prion protein accumulation in UK tissue samples. J Pathol. 2004 203, 733-739. 4 Andreoletti et al. (2006) Bovine spongiform encephalopathy agent in spleen from an ARR/ARR orally exposed sheep. J. Gen. Virol. 87, 1043-1046. 5 http://www.seac.gov.uk/statements/state260106.htm 5 © SEAC 2006 of the HPA National Anonymous Tonsil Archive that is collecting tonsils for vCJD infection prevalence estimation. • Defra and FSA tabled plans for studies to address recommendations made by the SEAC Sheep Subgroup for research on atypical scrapie6. It was noted that material for this research is in very short supply. Dr Peter Barrowman (Department of Environment, Food and Rural Affairs [Defra]) explained that Defra was looking to accumulate as much material as possible from the few atypical scrapie cases identified from TSE surveillance. Material would also be generated from challenge studies. Defra, the Food Standards Agency (FSA) and VLA are convening a group to consider priorities for use of the available material. A member suggested that whole heads could be collected at abattoir to increase the amount of available material. Dr Matthews explained that it was impracticable to collect whole heads. However, should sheep inoculated with atypical scrapie become diseased these animals would provide appreciable amounts of material for research. Inoculations of sheep with mouse atypical scrapie were under consideration as an additional method to generate more material but this approach may be inappropriate if phenotypic changes in strain occurred from passage in mice. • Unusual TSE test results obtained during routine surveillance from two French and one Cypriot sheep. Dr Matthews explained that the EU Expert Group on Strain Typing concluded that ring trial results of these samples were incompatible with the presence of experimental BSE in sheep. However, the unusual nature of the samples warranted further study so strain typing bioassays will be conducted. It is not yet possible to predict when results will be available. 6 http://www.seac.gov.uk/pdf/positionstatement-sheep-subgroup.pdf 6 © SEAC 2006 • Preliminary results from bioassays of one UK sheep TSE case identified in 2004 had given unusual results in biochemical tests. Dr Matthews explained that initial western blot of these samples was consistent with experimental BSE in sheep but that ring trial tests did not support this diagnosis. Strain typing bioassays had been conducted. One of the inocula had given an incubation period for clinical disease of 100 days in tg338 mice, which is inconsistent with BSE. Results of brain examinations were outstanding. • The SEAC Chair had attended a recent FSA stakeholder meeting in England and the SEAC Secretary attended equivalent meetings in Wales, Scotland and Northern Ireland to present and discuss the SEAC Sheep Subgroup statement. These workshops sought stakeholder views on options for possible additional precautionary measures in relation to atypical scrapie. The FSA Board would be returning to this issue in June 2006. The SEAC Chair had also attended the FSA Board meeting on 6th April 2006 when the Government’s contingency policy for BSE in sheep was discussed. • The study on transmission of BSE and vCJD in humanised mice7, considered in reserved business at SEAC 90, had been published. The minutes of the discussion have now been placed on the SEAC website. • Progress on recommendations made at SEAC 91 in relation to disposal of manure, crops and livestock at VLA Drayton. Mr Patrick Burke (Defra) explained that Defra would permit material from unchallenged animals and animals inoculated by the intracranial route to be composted and spread on arable land. Dr Matthews indicated that material from orallychallenged animals would continue to be composted and then used for coppice by VLA. It was likely that material from intracerebrally challenged animals would be treated in the same way. • The Creutzfeldt-Jakob Disease (CJD) Incidents Panel had been provided with the SEAC advice from SEAC 91 on the assessment of potential risks from medical implants containing bovine material. 7 Bishop et al. (2006) Predicting susceptibility and incubation time of human-to-human transmission of vCJD. Lancet Neurology. On line. 7 © SEAC 2006 • Sir William Stewart has agreed to chair a vCJD Patient Advisory Group being convened by DH to advise on the appropriate counselling and care for individuals defined as ‘at risk from vCJD for public health purposes’. Mrs Eileen Lawrence (DH) explained that the SEAC Chair and the Chair of CJD Incidents Panel had been invited to sit on this group. Requests for nominations to sit on this group had been submitted to relevant professional bodies and representatives from the National Prion Clinic and National CJD Surveillance Unit would be invited as special advisors. It was envisaged that the group would convene during the summer. ITEM 4 - AOB 10. There was no other business. http://www.seac.gov.uk/papers/draft92.pdf © 2006 Society for General Microbiology -------------------------------------------------------------------------------- Oral contamination with bovine spongiform encephalopathy (BSE) agent in susceptible PRNP genotype sheep results in widespread distribution of prion in the host. Because ARR homozygous sheep are considered to be resistant to transmissible spongiform encephalopathies, they have been selected to eradicate scrapie from sheep flocks and to protect the human food chain from small ruminant BSE risk. However, results presented here show that several months after an oral challenge with BSE agent, healthy ARR/ARR sheep can accumulate significant amounts of PrPSc in the spleen. http://vir.sgmjournals.org/cgi/content/abstract/87/4/1043 7 Bishop et al. (2006) Predicting susceptibility and incubation time of human-to-human transmission of vCJD. Lancet Neurology. On line. http://disc.server.com/discussion.cgi?disc=167318;article=2829;title=CJD%20WATCH see increase of sporadic CJD over the years ; if you look at 2003 there were 3 type unknown. wonder if they were the same or different than the unknown in 2005? considering the soup that has been brewing over here in the USA for years via the rendering of BSE and atypical TSE in cattle, CWD, Scrapie, a few TME cases (not too much due to scent gland, but there were a few rendered, but all this, and you have one hell of a recipe for a new strains of TSE in humans. then who knows what 'friendly fire' cases would look like from this soup via secondary transmission via medical/surgical/dental arena. ...TSS TSS
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