Summary of the 85th SEAC meeting held on 30 November 2004.

The Spongiform Encephalopathy Advisory Committee (SEAC) held its 85th meeting in Cardiff on 30th November 2004, when it discussed the following matters:

CURRENT ISSUES

SEAC was updated on three current TSE issues:

· The FSA / SEAC milk working group, established to provide advice to the FSA on research to develop diagnostic tests to detect abnormal PrP in milk from cattle together with assessment of results from tests of experimental samples, is expected to complete its work in the early part of 2005. It is anticipated that a report from the group will be provided at the next SEAC meeting.

· A paper by Wadsworth et al (published 11 November 2004) reporting that the phenotype and transmission of vCJD and BSE in transgenic mice expressing human PrP were profoundly influenced by polymorphisms at codon 129 of the PrP gene.

· A European Commission press release (28 October 2004) suggesting that a goat in France may have been naturally infected with BSE. Following this announcement, the Community Reference Laboratory expert group had concluded (25 November 2005) that, although the data available are consistent with BSE, a definitive interpretation could not be provided until further data from mouse bioassays were available in approximately two months.

CHRONIC WASTING DISEASE IN UK DEER

SEAC was asked by the FSA to consider the likelihood of chronic wasting disease (CWD) being present in UK deer and, if it were present, the possible risk posed to consumers from eating meat from infected animals. CWD is an endemic transmissible spongiform encephalopathy (TSE) of certain species of captive and wild deer in areas of North America.

SEAC noted that CWD has never been found in the UK or elsewhere in Europe but acknowledged that surveillance data on TSEs in deer are very limited. Although the origins of the disease are unknown, the committee considered there is good evidence that it is transmitted laterally between animals, possibly via contaminated environments, but the precise mechanisms are unclear. Additionally, it is possible that at least some UK deer species may be relatively susceptible to CWD, although red deer may be the species most likely to be susceptible because they are closely related to Rocky Mountain elk, one of the North American species affected.

SEAC considered that, although incomplete, there is no evidence from epidemiological or experimental studies to suggest that sheep or cows are susceptible to natural infection with CWD. Furthermore, the committee concluded there is no evidence of transmission of CWD to humans from consumption of venison but noted that data are extremely limited and it would be very difficult to detect a low level of infection.

SEAC also considered that, although a theoretical possibility existed, there is no evidence to suggest that BSE is present in UK deer. It was noted that a study to look at the potential susceptibility of red deer to BSE was at a very preliminary stage.

SEAC agreed to produce a position statement on CWD and UK deer.

HORIZON SCANNING

The committee was informed by representatives from DH, FSA and Defra about forthcoming issues that might require consideration by SEAC, including:

· estimation of the size of the vCJD epidemic, minimisation of the risks of secondary transmission of vCJD, development of diagnostic tests for vCJD, age distribution and susceptibility of vCJD infection (DH).

· development of diagnostic tests for BSE, possible public health risks of TSEs in sheep, development of contingency plans for TSEs in the food supply and changes to regulatory controls for BSE (FSA).

· examination of BARB cases (BSE cases Born After the Reinforced Ban), relaxation of BSE control measures and safe disposal of animal by-products (Defra).

TERMINATION OF CATTLE BIOASSAYS

The committee noted the proposed termination of FSA-funded cattle bioassays to examine the BSE infectivity in cattle tissues. Members stressed the importance of archiving appropriate tissues from the cattle bioassays to ensure maximum scientific information can be obtained.

PUBLIC QUESTION AND ANSWER SESSION

The Committee answered questions from the public about TSEs including the development of blood tests for TSEs, the number of sCJD cases and their genetic make-up, and the recent finding of possible BSE in a French goat.

MATERNAL TRANSMISSION OF vCJD

DH asked SEAC to consider the potential for maternal transmission of vCJD. The item was discussed in a reserved business session because it involved consideration of confidential medical information and unpublished data.

SEAC concluded that there is no evidence for maternal transmission of vCJD, but acknowledged that most of the relevant information is indirect rather than direct. Therefore, although it was considered that a hypothetical risk of maternal transmission is likely to be low, a risk cannot be ruled out.

 

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Page updated: 02 December 2004