Public summary of meeting on
9th March 1998

The Spongiform Encephalopathy Advisory Committee (SEAC) met on 9 March 1998 at the offices of the Ministry of Agriculture, Fisheries and Food, Whitehall Place, London.

The Committee conducted its regular review of research findings and the epidemiological information on BSE and nvCJD. In particular the Committee reviewed an abstract of American research showing that scrapie infectivity had been detected in muscle in transgenic mice. The Committee noted that the mice used in this experiment had been genetically engineered to artificially produce more of the normal PrP protein in muscle cells than in normal brain cells. (PrP is the protein which adopts an abnormal conformation in TSEs). The Committee concluded that the results showed that muscle cells have the potential to produce abnormal protein and that the assays which were in progress for infectivity in muscle of BSE infected cattle which did not involve a species barrier were important. The Committee also noted research in another neurological condition, idiopathic brainstem neuronal chromatolysis, which had potential to be confused with BSE on clinical grounds.

The Committee was informed that a new case of nvCJD in the UK had recently been confirmed. The total now stood at 24 and would be reflected in the next monthly summary of CJD statistics to be issued by the Department of Health on 6 April. The Committee noted that the number of BSE cases continues to decline in line with predictions.

The Committee, as part of a Government-wide initiative to increase the openness of advisory committees, discussed ways in which it could improve the transparency of its deliberations. The Committee welcomed moves to greater openness and expressed a willingness to participate in such moves. However it was considered that a mechanism to safeguard confidential scientific, patient, veterinary and commercial information that was crucial to its work would need to be built into the process.

The Committee noted the action being taken by Government following SEAC’s previous advice on human blood. The Committee considered that it was not necessary to change or add to its previous advice at this stage and agreed to review the position when the risk assessment was completed.

The Committee confirmed its previous advice on the use of bovine blood in animal feeds and saw no need to go beyond the existing controls.

The Committee noted the latest position with specified risk materials (SRM) in the EU and implementation of the SRM regulations in the UK especially with regard to controls on the spinal cord of sheep. They confirmed the previous advice; controls should prevent the use of sheep and goat vertebral column for production of mechanically recovered meat but production of tallow and gelatin, which involved a high degree of processing, could be permitted from sheep and goat vertebral column. The Committee went on to urge Government to pursue its plans for improving the epidemiological surveillance of scrapie in sheep and goats and to screen as many cases as possible using newly developed techniques, such as molecular strain typing using Western blot analysis of protease resistant PrP, to characterise the strains of TSE agent involved and to determine if any of these might be BSE.

The Committee reviewed the theoretical possibility that, in certain circumstances, BSE infectivity could be present in cattle which do not show the signs of clinical disease at any time during their normal life-span. Such a situation had not been detected in the UK cattle population, however there was evidence from experiments in mice that in certain conditions the TSE agent can persist in the animal without ever causing clinical disease. It will be important as the clinical disease in cattle declines to ensure that there is no such reservoir of latent BSE infection. The Committee considered that Government should initiate further research into this issue.

The Committee received data on BSE in imported cattle and, following discussions, asked to be kept informed about such cases on a regular basis.

The Committee noted that, in line with the recommendations of the SEAC review, an Annual Report of the Committee’s business would be produced beginning with the period up to April 1998.

SEAC
March 1998