Summary of the 81st SEAC meeting held on 25th February 2004.

The Spongiform Encephalopathy Advisory Committee (SEAC) held its 81st meeting in London on 25th February 2004, when it discussed the following matters:

UPDATE ON ‘TRANSFUSION’ vCJD CASE

SEAC was informed of a study set up to examine possible links between vCJD and blood transfusion. This study identified a case of possible transmission of variant CJD by blood transfusion. The recipient received blood in 1996 from a donor who was, at the time of donation, free of clinical signs of vCJD. The donor went on to develop vCJD in 1999 and the recipient of the blood transfusion died of vCJD in the autumn of 2003. Statistical analysis suggests that it is unlikely to happen by coincidence and SEAC agreed that this raises the possibility that the infection was transmitted by transfusion. However they noted that it is a single case and that the recipient had received blood before the protective measures of leucodepletion were adopted in 1998 in the UK, which it was hoped would reduce substantially the chance of transfusion of vCJD by blood. SEAC noted the importance of this study in identifying potential transfusion-associated cases.

vCJD UPDATE

SEAC was updated on the latest statistics from the National CJD surveillance unit. Up until January 2004, a total of 146 vCJD cases have been confirmed in the UK, including 7 cases still alive. All vCJD cases tested to date are of the same genotype at codon 129 of the PrP gene (methionine homozygous). Short-term analysis of the number of deaths from vCJD in the UK continues to show statistically significant evidence that the epidemic is no longer increasing exponentially and, at least in the short term, the epidemic may have peaked or reached a plateau.

UPDATE ON AMERICAN BSE CASE

SEAC received an update on the recent BSE case in the United States of America. SEAC was informed there were strict controls on imports of beef from third countries and that very little US beef was imported into the UK because of other trade restrictions. SEAC asked to be kept up to date on the US surveillance programme for BSE.

DISCUSSION OF ATYPICAL BSE CASES

SEAC considered the findings of a research paper recently published in the Proceedings of the National Academy of Science (Casalone et. al. (2004)). The researchers suggest that they have identified a second bovine amyloidotic spongiform encephalopathy which has a molecular signature similar to that of a subtype of sporadic CJD. SEAC agreed that the results were very interesting, but without information on the transmissibility, it was premature at this stage to conclude this was a new strain of BSE. SEAC agreed it would follow this research with interest.

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Page updated: 2nd March 2004