I would like to correct an error in the article "Scientists will test BSE mutation theory" ( THES , December 5). It mentions a recommendation made by Ferguson Smith to genetically screen BSE cases in cattle born after the reinforced ban (Barb) but incorrectly states that the Spongiform Encephalopathy Advisory Committee did not discuss this issue at its recent meeting. Seac covered the issue at length during a discussion on the origin of BSE in relation to Barb cases. A genetic basis, such as a mutation in the PrP gene, is only one of several possible explanations for BSE in Barb cases but, nevertheless, Seac has always been clear about the need to investigate this possibility.
Peter Smith
Chair, Seac