 |
From: TSS (216-119-136-146.ipset16.wt.net)
Subject: Re: THE SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE OPEN MEETING 11th February 2003
Date: February 11, 2003 at 11:05 am PST
In Reply to: THE SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE OPEN MEETING 11th February 2003 posted by TSS on February 11, 2003 at 11:03 am:
Paper No. SEAC 77/1 Draft Version
© SEAC 2003
1
SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE
Draft minutes of the 76th meeting held on 14th November 2002
At
The Hilton London Metropole
Edgware Road
London
Members: Professor P. Smith (Chairman)
Professor J. Ironside (Deputy Chairman)
Professor C. Bostock
Professor G. Bulfield
Professor R. Carrell
Mr P. Jinman
Professor H. Kimbell
Professor C. Masters
Professor I. McConnell
Dr J. Safar
Technical Advisors: Mr P. Soul (Defra)
Dr P. Barrowman (Defra)
Dr J. Stephenson (DH)
Ms A. Conroy (FSA)
Dr S. Dixon (FSA)
Observers: Dr A. Allman (BBSRC)
Dr S. Baxter (SERAD)
Dr P. Crook (EA)
Dr A. Douglas (DARDNI)
Dr J. Nielson (HSE)
Dr M. Simmons (NAWAD)
Professor J. Wilesmith (VLA)
Dr D. Matthews (VLA)
Assessors: Dr M. Bailey (Defra)
Mr A. Harvey (FSA)
Dr R. Jecock (DH)
Secretary: Dr C. Boyle
Paper No. SEAC 77/1
© SEAC 2003
2
Secretariat: Dr R. Pugh
Mr M. Pemberton
Dr A. Leigh
Dr C. Ravirajan
Also in attendance: Mr P. Comer ( Paper 76/4)
Paper No. SEAC 77/1
© SEAC 2003
3
Item 1 - Chairman's introduction
1.1 The Chairman welcomed Members and the Public to the open meeting,
and reminded the Public of SEAC's remit1. He pointed out that the
Committee currently had 13 Members of whom each is an independent
expert, selected through rigorous public appointment procedures.
1.2 The Chairman indicated it was the third open meeting of SEAC. The
reason for holding SEAC meetings in open was to provide the public
with an opportunity to observe the Committee at work.
1.3 The Chairman explained to members of the public that the meeting
was essentially business as usual for the Committee and asked
Members of the public to raise questions or points through the
Secretariat or via the SEAC website (www.seac.gov.uk).
1.4 The Chairman welcomed guests present at the meeting, specifically Mr
Philip Comer from DNV consulting who would present item 6.
1.5 The Chairman informed the Committee that apologies of absence
had been received from two Members, Professor R. Anderson, and
Professor A. Aguzzi.
Item 2 - Approval of draft minutes from 11 September SEAC meeting
(SEAC 76/1)
2.1 Members considered the draft Minutes from the previous meeting.
2.2 The Chairman drew Members attention to the first sentence of
paragraph 7.11, under item 7 - Transmission of prion diseases by
blood transfusion. Members agreed that the sentence did not quite
reflect the discussions. Members accepted the sentence should be
amended to read 'Members queried whether haemophiliacs and others
who received large quantities of blood products, and children, might be
at greater risk'.
Action: SEAC Secretariat
2.3 The Committee sought clarification with respect to paragraph 3.4,
under agenda item 3. Concern was expressed over the sentence “Ad
hoc subsidiary peer review panels will be set up whenever there is a
call for research proposals in an area which is outside the collective
expertise of the programme panel”. The Committee agreed that the
1 The remit of SEAC is 'to provide scientifically based advice to the Department for Environment, Food
and Rural Affairs, the Department of Health, devolved administrations, and the Food Standards
Agency on matters relating to spongiform encephalopathies, taking account of the remits of other
bodies with related responsibilities.'
Paper No. SEAC 77/1
© SEAC 2003
4
paragraph should be redrafted to indicate clearly that "all" proposals
received will go to external peer review.
Action: SEAC Secretariat
2.4 With respect to paragraph 8.13, Members noted that the measures
proposed (under the code of practice) would effectively undermine
existing research projects funded by the European Union and World
Health Organisation Diagnostics Group. It was agreed that although
the current draft was correct, it would be useful for the names of the
funders of “overseas research projects” to be noted.
Action: SEAC Secretariat
2.5 Members agreed to accept the draft minutes (with suggested
modifications) as final.
Item 3 - Matters arising (from agenda item 2)
3.1 With respect to paragraph 7.11, Members were informed by the
Department of Health that the individual risk for haemophiliacs is likely
to be low. Members were reminded that since 1998 all plasma for
plasma products preparation has been obtained from outside of the
UK, from countries where BSE is not present. Members accepted that
these comments should be dealt with by recording them as a footnote
to paragraph 7.11 of the minutes of the SEAC meeting on September
11th 2002.
Action: SEAC Secretariat
Item 4- vCJD update
4.1 The Committee conducted its regular review of epidemiological
information on vCJD. It was informed that the total number of definite
or probable vCJD cases in the UK, as at 14th November 2002, was
129, 12 of whom were alive. There were 71 male and 58 female cases
in the UK. The mean age at death was 29 years with a range from 14
to 74 years. The mean age at onset was 27 years. The median
duration of illness was 13 months with a range from 6 to 39 months. It
remained the position that all of the cases tested for their prion protein
(PrP) genotype (105 in total), were Methionine/Methionine at codon
129 of the PrP gene (about 37 per cent of the UK population being
Methionine/Methionine).
4.2 There were 6 vCJD cases in France, 1 in the Republic of Ireland, 1 in
Italy, 1 in the USA and 1 in Canada. None of the cases from France,
nor the case from Italy had a history of residence in the UK. The cases
Paper No. SEAC 77/1
© SEAC 2003
5
reported in Ireland, Canada and US had a history of UK visits or
residence in the late 1980s.
4.3 The Committee noted the results from an analysis from the Public
Health Laboratory Service (January 1994 – September 2002) which
showed the observed and expected onsets and deaths for variant CJD
assuming an exponential growth (where it is assumed that the numbers
were to go up by a constant percentage each year). Currently the
analysis showed that the trend in the number of vCJD cases had
increased, on average, by 16 % per year (since 1994) for onsets and
17 % per year for deaths (since 1995). However, the statistical analysis
showed that when looking at onsets and deaths by quarter, a model
that allows for a departure from an increasing exponential trend (a
quadratic trend on a logarithmic scale), appeared to be a better fit to
the data than a model which does not allow such a departure.
4.4 This quadratic analysis showed there was statistical evidence to
suggest the epidemic may no longer be increasing at the rate seen
previously. This may indicate the epidemic has reached a peak, at
least in this particular subset of individuals. However, this is a
preliminary indication and cannot be regarded as definitive evidence
that the epidemic has peaked and is in decline; the figures may
represent a slowing down in the underlying increase or there may be a
second peak at a later date. Also the finding is not highly statistically
significant. If the epidemic has reached a peak, then clearer evidence
of this should become apparent with further data in the next few
quarters.
4.5 Examination of the figures showed there was no statistical difference
between the trends in males and females either for disease onset or
deaths.
4.6 The Committee noted that when interpreting changes in rates of
disease onset and death, there was a need to be aware of the impact
of trends in declining autopsy rates and possibly declining referral
rates. Since 1999 there has been an overall marked decline in
autopsies, particularly in patients with probable vCJD. The Committee
agreed this may influence case ascertainment for vCJD. The annual
number of referrals of suspected cases of CJD to the National
Creutzfeldt Jakob Disease Surveillance Unit (NCJDSU) increased after
1996 (when variant CJD was identified) to over 160 per annum with the
maximum in the year 2000. To date this year the number of referrals
was less than 120.
4.7 The Committee noted the importance of continuing surveillance. In
genotypes other than Methionine/Methionine, a BSE sourced infection
may have different clinical features. Therefore, a high referral rate is
essential to ensure potential cases are not missed. In Switzerland there
had been a recent increase in the number of sporadic CJD cases; a
similar trend has not been observed in the UK, although the numbers
Paper No. SEAC 77/1
© SEAC 2003
6
have varied since surveillance began in 1990. Presently it could not be
ruled out that the recent increase in sporadic CJD in Switzerland was a
chance finding, but it would be important to ascertain if the apparently
increased numbers of cases was sustained for a longer period.
4.8 The Committee agreed it was still not possible to forecast longer-term
trends of the vCJD disease with confidence. The Committee was
informed that details of the analysis were available on the National CJD
Surveillance Unit website: www.cjd.ed.ac.uk.
Item 5 - Report back from the SEAC Epidemiology Sub- Group Meeting
5.1 In the absence of Dr Noel Gill, Chair of the SEAC Epidemiology Sub-
Group, the DH Secretary to the Sub-Group provided members with a
summary of the key points arising from the meeting of the Sub-Group
on 27th September 2002. Four substantive items were reported. The
first item was a presentation by the PHLS of provisional data on vCJD
trends for the third quarter of 2002 (as discussed above). For the first
time since 1996, provisional analysis of the quarterly data for deaths
from vCJD showed a statistically significant departure from an
exponential increase. The SEAC Epidemiology Sub-Group considered
that it was premature to conclude that this was a decline in the death
rate from variant CJD, or that the epidemic has reached a peak. It was
considered that at least another three-quarters (i.e. 9 months) would be
needed before starting to draw any firmer conclusions.
5.2 The second item was the DNV report, commissioned by the FSA, on
‘Sources of BSE infectivity – Historical Uses of Mechanically
Recovered Meat’. The SEAC Epidemiology Sub-Group considered that
this was a valuable survey in terms of capturing historical information,
particularly the retrospective study on uses of mechanically recovered
meat. Members considered it was possibly one of the last opportunities
to gather such information, as peoples’ recollection of what had
happened many years ago inevitably fades. It was noted that the report
indicated that probably about twice as much mechanically recovered
meat (10%) had come from older adult cattle than had been estimated
in an earlier study1 (5%).
5.3 It was concluded that this might aid scientists to better understand the
exposure of the population to meat that was potentially infected with
the BSE agent. The NCJDSU commented that following the publication
of the report they were examining their questionnaire, administered to
the relatives of patients, regarding the consumption of certain food
products.
5.4 A third item was a report on a recent investigation into geographically
associated cases in North-East England. Careful investigations are
1 Cooper, J. and Bird, S.M. (2002). UK dietary exposure to BSE to beef in mechanically recovered
meat: by birth-cohort and gender. Journal of Cancer Epidemiology and Prevention 7, 59-70.
Paper No. SEAC 77/1
© SEAC 2003
7
undertaken whenever there is an indication of co-location of vCJD
cases. In this instance, there was no evidence that there were any
common linkages, such as unusual butchery practices, as had been
identified in the investigation of the statistically significant geographical
cluster identified in Queniborough (North Leicestershire).
5.5 The Sub-Group reviewed a paper by Hilton et al. (2002)2 which
reported the first positive finding of abnormal prion protein in a
retrospective study of some 8000 anonymised appendix and tonsil
samples. The Sub-Group considered the significance of this finding to
be unclear. However, Members were pleased to note the CMO’s recent
decision to establish a prospective collection of 50,000 tonsil samples
to enable a much wider study to be undertaken should it be required in
the future.
Item 6- Sources of BSE infection – Historical uses of Mechanically
Recovered Meat (MRM) (SEAC 76/4)
6.1 Mr Phillip Comer of DNV Consulting presented the results of a study to
establish the main sources of potentially infected material in food
during the period of the BSE cattle epidemic. The study focused
exclusively on the time period before the main controls for human
health were implemented (1980 – 1995). The study had been
commissioned by the Food Standards Agency following requests from
the SEAC Epidemiology Sub-Group and the Board of the Food
Standards Agency. A draft of the report was presented to the SEAC
Epidemiology Sub-Group on 27 September 2002, prior to publication
on 10 October 2002 (see above). No conflicts of interest were
declared by Members.
6.2 The study identified two main sources of potential infectivity during the
period investigated:Mechanically Recovered Meat (MRM), which may
have included spinal cord and dorsal root ganglia; and head meat, due
to potential contamination at slaughter. The findings suggested that
MRM had been used primarily in economy burgers and economy frozen
minced meat. According to some sources, MRM was not used in baby
food due to the possibility of presence of bones during the extraction
procedure. However, others reported that experimental work on gentler
flesh/bone separation processes had been carried out and MRM
extracted using these processes may have been used in baby food. The
use of head meat was reported to be primarily used in the manufacture
of minced meat and a wide range of burgers. The quantities of MRM and
head meat used during the period covered by the study were estimated
at 5,000 tonnes and 10,000 tonnes per annum respectively.
2 Hilton D., Ghani A., Conyers L., Edwards P., McCardle L., Penny M., Ritchie D., Ironside
J.W. (2002) Accumulation of prion protein in tonsil and appendix: review of tissue samples.
BMJ, 325, 633-634.
Paper No. SEAC 77/1
© SEAC 2003
8
6.3 The Committee was informed that the results from this study differed
from that reported by Cooper and Bird in three main respects. Firstly, a
low level of MRM production in 1988/89, peaking in 1998 to 5,000
tonnes per annum was reported by the Cooper and Bird study (Note: see
paragraph 6.4). Secondly, this study indicated that only 5% of MRM was
produced from older animals, compared to 10% reported in the DNV
study. Thirdly, the Cooper and Bird study reported that the majority of
MRM was used in the manufacture of burgers, whereas the DNV study
estimated that similar amounts were used in retail minced meat and
burgers.
6.4 The Committee discussed the study and the implications of the results.
The Chairman noted that given the various controls on the production of
MRM from 1995 onwards, it was surprising that the Cooper and Bird
study had reported a peak in MRM production in 1998. It was agreed
that clarification would be sought on this particular point2.
6.5 Members asked if information was available on the use of exported
MRM and whether it may have been re-imported into the UK after
processing abroad. The Committee was informed that there was a world
trade in MRM, and it was mainly exported as a frozen product to Africa.
As such, it was considered that the potential for re-import would be
small. Members raised the issue of whether the export of UK cattle
brains to France, as reported in the study, could contribute or account for
the six cases of vCJD in France. It was noted, however, that it was not
possible to relate these cases specifically to the export of brains, as
France was a major importer of UK beef during the BSE epidemic.
6.6 Members asked if it was possible to quantify the production, and
therefore the market share of those companies interviewed in the study.
Members were informed that all of the main MRM producers had been
interviewed, and these would have accounted for 90% of the total UK
MRM production.
6.7 Members asked if purchasing practices of institutional buyers could be
used to identify specific groups of consumers who may have been
exposed to those products. The Committee was informed that whilst
guidelines existed prohibiting the use of MRM in purchased processed
products, institutional buyers were under constant pressure to reduce
costs. Additionally, it would be difficult for institutional buyers to know if
MRM was used in a product or not. In response to a query, it was
confirmed that data on vCJD patients, held by the vCJD Surveillance
Unit, did include information about where and when patients went to
school, but this would not include information relating to the use of MRM
products in school catering or the suppliers. It was acknowledged that
obtaining historical information of that nature would be very difficult.
2 The Cooper and Bird study reported that beef MRM peaked at 5,000 tonnes in 1987, was nil in 1989
but recovered to 2,000 tonnes in 1995 when it ceased altogether.
Paper No. SEAC 77/1
© SEAC 2003
9
6.8 The Committee was informed that results from recent work undertaken
by Professor Paul Brown had shown that high-pressure treatment can
result in a reduction in TSE-infectivity. Members queried if the pressure
used in MRM production could have a similar effect. Members were
informed the pressures used in the MRM production process were likely
to be significantly lower than those used in the extreme high-pressure
experiments undertaken by Professor Brown.
6.9 Members queried whether consumers may have been exposed to beef
products unknowingly, as MRM may have been used as a filler in the
manufacture of other meat products, such as pork sausages, without
requirement for declaration on the label. Members were informed that it
was unlikely that beef MRM would have been used in products such as
pork sausages, these were likely to have included pork MRM. Beef
MRM may have formed the beef content in sausages containing both
pork and beef products, albeit at a relatively small volume.
6.10 Members enquired as to the use of the thymus, which was reported in
the study to have been frozen and sent for use in the pharmaceutical
industry. It was understood that a product called thymozine was being
produced, using an acid extraction process, by at least one company in
Italy.
6.11 The Chairman acknowledged that the nature of the study, and the way in
which it had to be conducted, would have inevitably left uncertainties due
to the lack of available documentary evidence. Members agreed that the
information contained in the report was very useful and demonstrated
the extent to which the population would have been exposed to
potentially infected material through the consumption of economy
burgers and minced meat. The extent to which MRM was used in
minced meat was of particular interest since it was a product that would
have been commonly consumed as part of the diet, which may help to
explain why the CJD Surveillance Unit had not been able to find any
distinctive features in the diet of vCJD cases. Members noted that the
Food Standards Agency intended to undertake a study into historic
butchery practices, which would take account of the comments made by
the Committee in relation to the MRM study.
Item 7- Department of Health Annual research Report (2001/2002)
(SEAC 76/5)
7.1 Dr. J. Stephenson presented the key issues from the Department of
Health (DH) Annual Report on TSE-Related research. No conflicts of
interest were declared by Members.
7.2 Members noted that DH had contributed over £5 million towards TSE
related research last year (2001/2002). The DH funds research to
inform policy needs on human TSEs in the areas of epidemiology and
surveillance, blood safety, tissue infectivity and strain typing, diagnosis
Paper No. SEAC 77/1
© SEAC 2003
10
and detection, the development and assessment of therapeutic drugs,
and decontamination.
7.3 The Committee was informed that following the Hunter et al1
publication on the transmission of TSEs through blood transfusion in
sheep, the DH had started planning experiments to test if the
precautionary measures in place with respect to human blood used for
transfusion are sufficiently robust to adequately protect against vCJD
transmission. It was anticipated that this work would start next year.
7.4 The Committee noted that one of the difficulties in the diagnosis of
vCJD was the lack of a diagnostic test for detection of pre-clinical
disease. A reliable test to detect infectivity in accessible body tissues or
fluids was considered crucial. The Committee was informed that a
number of new studies specifically addressing this issue have been
funded by the UK funders of TSE research. This had substantially
helped the research activities in this area. The DH is also considering
the practical and ethical issues of testing, should a diagnostic test
become available, and plans to hold workshops to discuss these issues
in the coming months. This proactive approach will help speed up the
implementation of a diagnostic test when it becomes available.
7.5 There has been some progress in the development of therapeutic
drugs for vCJD in the past few years and the DH has funded three new
drug development projects with Cranfield University, the Welsh School
of Pharmacy, and the Centre for Applied Microbiology and Research
(CAMR).
7.6 The Committee was updated on the progress of research into the
decontamination of surgical instruments. A number of projects are
nearing completion and a number of novel technologies may soon be
available for formal evaluation by the NHS. In addition, DH has been
approached by two companies: TSO3, who are using ozone to
decontaminate surgical instruments, and the British branch of the
American company ‘Steris’, who have a technology which they believe
could inactive prion proteins.
7.7 The Members were informed that the DH was in the process of setting
up a Decontamination Science and Engineering group to facilitate the
transfer of laboratory findings into a practical day-to-day situation for
the NHS. The remit for the group is still under consideration and will
need to be approved both by the NHS Decontamination Strategy
Group and by Ministers. The Committee noted that the progress in this
area was encouraging, but acknowledged that it would take some time
before it could be applied to routine use in the NHS.
7.8 One Member queried the progress on the DH-funded research
projects, which are using Immuno Capillary Electrophoresis (ICE) to
1 Hunter et al (2002) Transmission of prion disease by blood transfusion. Journal of General Virology
83
Paper No. SEAC 77/1
© SEAC 2003
11
detect prions in blood. The Committee was informed that the DH has
funded two projects which are using ICE. A third project is being
carried out at VLA, and funded by Defra, which is working to develop
and validate the ICE technology for the detection of prion protein in
blood from scrapie-affected sheep. The VLA study is ahead of the DH
work due to availability of animal blood samples. This work has
demonstrated that the ICE technology can detect PrPsc at certain time
points early in the incubation period. However a number of practical
issues need to be resolved before this technique can be routinely
applied. All three groups are collaborating in order to resolve these
issues.
Item 8 - Update on project M03016 – Determination of abnormal prion
protein in the milk of cattle experimentally infected with the BSE agent:
SEAC/INF/75/22
8.1 Dr Steve Dixon of the Food Standards Agency provided the Committee
with an update report of the work that had been commissioned by the
FSA to look at whether the BSE prion could be detected in the milk of
cattle experimentally infected with the BSE agent. This particular study
had been commissioned despite previous studies failing to detect BSE
infectivity in milk, and it was emphasised that no new safety concerns
had emerged regarding milk but more sensitive testing methods were
becoming available. Members were informed that the update report only
covered the phase of the study relating to the development and
validation of the analytical methods that would be used. Members
declared no interests.
8.2 Dr Steve Dixon outlined the concerns of the FSA relating to this phase of
the study, which related to i) the quality systems and the data quality; it
was important that the study was fully documented with a
comprehensive audit trail, and ii) the methods of analysis. An
independent audit had been commissioned by the FSA using the
company “Risk Solutions”, which would focus on sample collection,
labelling, storage, transport and handling; and would also include all of
the analysis.
8.3 With regards to the methods of analysis, the Committee was informed
that the validation would be reliant on the spiking of milk samples with
BSE infected cattle brain homogenate. However, there was a concern
that if PrPsc were present in milk, it was highly probable that it would be
present in a different form from that which was present in brain tissue. If
present in body fluids, PrPsc was more likely to be dispersed and quite
possibly in a non-aggregated and soluble form. As a result, the FSA
was collaborating with the VLA and obtaining material from an
experiment, commissioned by Defra, to generate a soluble
unaggregated form of the BSE prion.
Paper No. SEAC 77/1
© SEAC 2003
12
8.4 The independent audit was expected to be completed by the end of
2002. The ongoing validation process was expected to be completed
towards the end of January 2003 or the beginning of February 2003, with
the analytical protocols expected to be submitted for peer review
towards the end of February 2003. Providing this timetable is achieved,
the FSA should be in a position to take a decision on whether to proceed
with the analysis of the experimental milk samples or not towards the
end of March 2003 or during early April 2003.
8.5 Members discussed the importance of this study in relation to the
development of antibodies to produce the right immunoaffinity extraction
of any potential BSE PrP-like proteins. Reservations were expressed
about the progression of the science relating to this particular area of
work. Members commented that the need for a disease-specific antibody
was not necessary for this particular study and that to produce such an
antibody might take a considerable time, as previous attempts to do this
had not been successful. Reagents were already available that could be
used in conjunction with other properties to distinguish between the two
forms of PrP (disease specific PrPsc and normal form PrPc).
8.6 Members were told that the validation phase of the study would focus on
the cellular fraction of milk, which had been spun down and stored. For
this first phase of the study, existing test methods approved by the EU
would be used: the Prionics test, a variation between the Prionics and
the Biorad test, and the Biorad test. Other fractions of the milk would be
looked at using the monoclonal or recombinant antibodies as part of the
second phase of the study. Members were informed that scientists at
Leicester University, who were developing this particular area of work,
had isolated 20 different antibody clones of which five were showing
significant promise and had the potential to develop and provide the
immunoaffinity substrates and antibodies needed for the second phase
of the study.
8.7 Members discussed the validation methodology and expressed concern
over the spiking of milk with brain tissue, and asked whether the
validation might be performed on sheep blood as this was known to
contain the BSE agent in experimentally infected animals. It had been
demonstrated that sheep had been infected with BSE and scrapie via
blood transfusions including buffy coat fractions. Therefore, in terms of
validating the methodology, it was suggested that sheep blood would
provide a better medium for testing whether small amounts of disease -
associated PrP could be detected in a fluid tissue. It was not clear
whether sufficient archived infected blood samples existed for this
purpose, and so an alternative suggestion was to use spleen from
scrapie infected sheep; more samples would be available and Western
blot could be used to check that the abnormal PrP was present in the
sample before using it to spike milk.
8.8 Dr Matthews explained that the use of blood or other tissues had not
been considered as part of the original project design. Dr Matthews said
Paper No. SEAC 77/1
© SEAC 2003
13
that it was important to take a staged approach to account for new
developments rather than delay the experiments per se, as delays may
hinder policy development on this issue. It was suggested that
inoculation of milk samples into bovine transgenic mice may provide a
sensitive assay. One Member agreed with this suggestion adding that
the mouse bioassay has hitherto been the gold standard, although
bovine transgenics are now several-fold more sensitive than R3 mice.
8.9 Members were informed that the Food Standards Agency had issued a
call for research using bioassays to test milk samples. It was anticipated
that transgenic mice studies would feature in the research proposals
submitted in response to this call; and that such a study would
complement the ongoing milk study. Again, it was recognised that there
would be issues of validation with respect to future work, especially in
terms of the preferred method of collection and fractionation.
8.10 Members asked if the mammary gland, was included in the ongoing
pathogenesis study. Members were informed that the mammary gland
would be examined post mortem and at present all the milking cows
were still alive. Members were informed that previous pathogenesis
studies had not included dairy cows and therefore there was insufficient
archived material available to examine. It was also confirmed that the
likelihood of obtaining sufficient milking cows, which are clinical suspects
for natural BSE, is very low – given the current difficulties in sourcing
BSE suspects to meet other requirements.
8.11 Members sought clarification on the definition of milk samples that would
be tested in the study. Members pointed out that specific milk samples
(samples with ~ 400,000 cell count) had been mentioned in part of the
study. However Members suggested that this may be suitable as a cut
off for a bulk sample but individual samples may be in the region of a
million plus cell counts. It was therefore important to establish whether
bulk sampling, individual sampling, colostrum sampling or post mastitis
sampling would be used as part of the study. Members were referred to
the appendices of the meeting paper, which detailed the processing,
archiving and sampling of the milk.
8.12 Members commented that the work relating to milk was critical, since it
was a product derived from older animals and was not subject to the
over thirty month rule. Whilst it would be a mistake to re-create a whole
series of experiments, important issues had been raised about antibody
technologies and it was considered that further discussion in the form of
a Sub-Group would provide the best mechanism for taking the work
forward.
8.13 In drawing the discussion to a close, the Chairman agreed that the
formation of a Sub-Group would be a good way forward, but it was
important to ensure that any further discussions did not slow the
progress of research. It was suggested that the Sub-Group should
consider not only the ongoing study, but also the additional study that
Paper No. SEAC 77/1
© SEAC 2003
14
would be commissioned by the Food Standards Agency. The Chairman
acknowledged the difficulties encountered by those who were
responsible for undertaking the study.
Action: SEAC Secretariat to arrange a Sub-Group meeting.
Item 9- Scientific Advisory Committees – Reviews and Codes of
Practice (SEAC 75/4)
9.1 Dr. Catherine Boyle, the SEAC Secretary, presented this item.
9.2 Members noted the review reports from the Food Standards Agency1
(FSA) and the Office of Science and Technology2 (OST). These
guidelines were drawn up in the light of lessons learned from the
Phillips Inquiry. It was recognised that there was some overlap in
terms of recommendations arising from the two reviews.
9.3 The SEAC Secretariat had studied both reports and identified seven
key areas where further action is required. These action points were
listed in the paper (SEAC 75/4) and Members were requested to
contact the SEAC Secretariat if they wished to comment. The
Secretariat would update the Committee on progress made towards
addressing the main recommendations, which are relevant to SEAC.
9.3 Members noted that SEAC is undergoing a quinquennial review,
which is a separate exercise to the OST and FSA reviews. It was
noted that the recent Lancet article regarding the qiunquennial review
of SEAC was factually inaccurate, and that the Secretariat would be
writing to the Lancet advising the editor accordingly.
Action: SEAC Secretariat
Item 10 - AOB
10.1 The Chairman referred to the agreed minutes for the SEAC meeting
held on 10 April 2002, and drew Members’ attention to the first half of
paragraph 7.3 under agenda item 7 - Proposals for further evaluation of
the differential diagnostic test for TSEs in sheep. Members agreed that
the paragraph was not clear and accepted the proposed change which
should revise the paragraph to read: 7.3.1 'Experiments had also been
carried out to assess if the natural breakdown of sample tissue
between collection and testing (autolysis) affected the discriminatory
ability of the test. Analysis suggested that although autolysis does
effect the pattern seen on the western blot to some degree, the ability
1 The Food Standard Agency’s Report on the Review of Scientific Committees-published in March
2002
2 The Office of Science and Technology’s Code of Practice for Scientific Advisory Committeespublished
in December 2001
Paper No. SEAC 77/1
© SEAC 2003
15
of the test to distinguish between scrapie and BSE is not lost. However
it does reduce the effectiveness of the signal antibody to bind to the
protein.' The second half of paragraph 7.3 remained unchanged and
was to be referred to as 7.3.2 .
Action: SEAC Secretariat
10.2 The Chairman reminded the Committee that the next meeting for
SEAC was scheduled for Tuesday 11 February 2003. http://www.defra.gov.uk/ SEAC No: 77/4
OFFSPRING CULL: PAPER FOR SEAC MEETING ON 11th
FEBRUARY 2003 http://www.defra.gov.uk/ Agenda
77th meeting on Tuesday 11th February 2003.
Department of Trade and Industry Conference Centre
1 Victoria Street, London.
SW1H 0ET. http://www.defra.gov.uk/ TSS
Follow Ups:
Post a Followup
|
