Public summary of the meeting on
17th July 2000

The Spongiform Encephalopathy Advisory Committee (SEAC) met at the offices of the Ministry of Agriculture, Fisheries and Food (MAFF), Whitehall Place West, London on 17 July 2000.

Members were informed that Dr Mike Painter had decided to stand down from the Committee, having served since 1996. Members recorded their thanks for his valuable contribution during this period of service. The Committee were informed of Ministers' decision to re-run the exercise to find a new Chair for the Committee and to advertise to fill the vacancies left by the resignation of Dr Painter and by the earlier resignation of Dr Peter Goodfellow.

Review of BSE controls

Sir John Krebs updated the Committee on the progress of the Food Standard Agency's review of BSE controls.

The next stakeholders' meeting to discuss the review of BSE controls was to be held in public on 18 July. Sir John indicated that on the basis of the assessment so far, he did not feel it was likely there would be a recommendation for immediate relaxation of any of the controls in the three areas under consideration - the over thirty months rule, SRM controls and the feed ban. The issue to be considered was more one of identifying at what point in the future it might be appropriate to relax the rules taking account of the EU dimension, progress with science and disease incidence. However, he stressed that these were preliminary views and they could change as the report of the review was finalised. A first draft of the FSA's report would be ready in September and Sir John would update the next SEAC meeting, on 29 September, on progress.

Variant Creutzfeldt Jakob Disease update

The Committee conducted its regular review of case data and analysis of the current level of incidence of vCJD. Members also considered reports of a number of vCJD cases in an area of Leicestershire. Because of the high level of public and media interest in this agenda item, the Committee took the exceptional step of issuing a news release on these matters after the conclusion of the meeting on the 17 July. The text of the news release, including a correction of a minor error in the original version, is set out below.

'The Committee conducted its regular review of epidemiological information on variant Creutzfeldt Jakob Disease (vCJD) and noted that there are now 76 "definite" and "probable" cases, including 7 "probables" still alive. The Committee noted that the number of cases reported now indicated a statistically significant rising trend of around 20-30% per annum to date (i.e. currently corresponding to some two to four additional cases each year further to those already being reported) but concluded that it was too early to assess the extent of this trend over coming years, or forecast accurately the ultimate size of the vCJD epidemic.

The Committee also noted that four "definite" and one "probable" case of vCJD had occurred in an area of Leicestershire. The higher number of cases in that area is unlikely to have occurred by chance but this cannot be completely ruled out. The Committee welcomed the fact that a locally based investigation was now underway to look into the circumstances of this apparent cluster, as this could well throw new light on the mode of transmission of vCJD, which would also have implications for our understanding of the national epidemic. The Committee noted that the local investigation was likely to report within the next few months, and asked to be kept closely informed of developments.'

BSE Epidemiology and first case of BSE in a cow born after 01 August 1996

The Committee also conducted its regular review of research findings and epidemiological information on BSE. So far this year, restricted BSE cases in cattle were 39% lower than during the equivalent period last year. There was encouraging evidence in the figures which was consistent with a significant fall in exposure levels in cattle born in the 1994/96 period compared with cattle born previously, indicating that the feed ban was increasingly effective over that period.

Members discussed the recent announcement of the case of BSE in a cow born on 25 August 1996 - the first recorded case of BSE in a cow born after 01 August 1996, the date when further measures to improve feed security were considered to be fully effective. The investigation into the background to the case had revealed that the cow's dam had been found dead on the farm three months after the birth of the affected animal with no apparent pre-clinical signs of BSE, rather than slaughtered as a casualty as previously reported. The cow's dam was four years old at death.

Members welcomed MAFF's investigation into the possible routes by which the animal may have been exposed to the BSE agent although they acknowledged it would be difficult to come to definitive conclusions. They noted that it had been predicted that a small number of BSE cases would be born after the implementation of further measures assuming the possibility of maternal transmission, although direct exposure to residual contaminated feed could not yet be ruled out in this case. Members agreed that the nature of existing control measures meant that there was no cause for concern with respect to the safety of meat as a result of this case.

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Dentistry and the use of dental instruments

The Committee was assisted by an oral pathologist, who was also a representative from the British Dental Association, in undertaking an analysis of whether any significant risk of person to person transmission of either sporadic or variant CJD might arise from dental surgery. The Committee concluded that there were no current grounds for recommending changes to procedures involving dentistry, but reiterated the need for thorough cleaning and sterilisation practices to be observed in respect of used instruments. In addition, the Committee recommended that further research be undertaken to improve our knowledge, in particular to analyse oral tissues from vCJD patients for any presence of abnormal prion protein. The Committee also proposed that oral tissues be subject to a theoretical risk assessment modelling analysis, similar to that already underway for other body tissues with respect to surgical instrument use.

Disposal of meat and bone meal (MBM) derived from specified risk material (SRM) and over thirty month scheme carcasses by landfill

The Committee was asked to consider a quantitative risk assessment of the disposal of meat and bone meal derived from specified risk material and over thirty month scheme carcasses by landfill, prepared in response to a request from the Committee at its June 1999 meeting.

The Committee was asked whether, in the light of the results of the risk assessment, it held to its earlier published (June 1999) view that landfill was an acceptable outlet for MBM of any origin, although it retained a preference for incineration. The Committee reiterated that it had a strong preference for incineration as the favoured route for the disposal of MBM and were uneasy about the use of landfill for the disposal of this material. If there were cases where incineration was not practical the Committee felt it would be preferable for any material going to landfill to be pressure-cooked first or possibly stored above ground prior to incineration.

Regular updates, updates on agenda items from previous meetings and other matters arising

The Committee received its regular progress report on Government funded research projects. A paper on scrapie monitoring would be presented to the Committee at its September meeting.

The Committee also received a report on current progress on the EU's proposals on specified risk materials and an update on MAFF's plans for the establishment of a national sheep genotyping scheme. A report from the joint Chief Medical Officer/SEAC Epidemiology Sub Group responsible for assessing information about vCJD and developing as far as possible advice on trends in the disease was agreed by the Committee and has been passed to the four UK Chief Medical Officers. A key conclusion from the report is that, because of the many uncertainties that surround this disease, it remains too soon to be able to make soundly based predictions about the future course of the epidemic.

The cases of suspected BSE reportedly found in sheep in the US were discussed briefly by the Committee. There was however, insufficient information available for the Committee to form an opinion and further enquiries were currently under way. Any further information would be reported back to the Committee as it became available.

The next meeting of the Committee will be held on the 29th September 2000.

SEAC
August 2000