|
|
|
|
|
|
|
The
Committee agreed that its remit was very wide.
|
|
|
The
Committee felt additional experts could be involved for particular
topics as necessary.
|
|
|
Overview
of developments in research
|
It
was proposed that there would be one overall joint coordinating
committee to oversee the AFRC and MRC research programmes.
|
|
|
|
Research
on the neuropathology of BSE showed consistent pattern of lesions
suggesting, unlike scrapie, a single strain and route of infection.It
was also reported that there had been positive intracerebral transmission
of BSE to negative-line sheep reported.The Committee confirmed that
the new information had not altered their perception about the probable
lack of hazard of BSE to humans.
|
|
|
Non-food
uses of bovine material
|
MAFF
and DH were to investigate the possible use of bovine and ovine
tissues in products (such as cosmetics); this work remained high
priority.
|
|
|
|
Concern
was expressed that the full range of hypotheses for the recent increase
in reporting had not been considered. It was agreed that MAFF would
arrange for the Committee to receive data on the progress of the
disease.
|
|
|
Breeding
from BSE offspring
|
The
Committee was not convinced of the line proposed by MAFF concerning
advice against the use for breeding of the offspring of BSE cows.
The incidence of subclinical infection invalidated any action proposed.
Other consequences identified were the loss of certain useful cattle
genes and of public confidence in the meat trade. With the expected
elimination of the disease (barring horizontal transmission), the
new measures might accelerate this only slightly.
|
|
|
Breeding
from BSE offspring
|
The
Committee made clear, after a request for clarification from MAFF,
that it wished to amplify its previous advice on breeding. It was
unknown whether BSE spread naturally among cattle, but even 100
per cent maternal transmission would not sustain the epidemic. The
Committee issued a statement on the issue of breeding and it was
released attached to a press release from MAFF.
|
|
|
|
The
CMO had sought the endorsement of the Committee on the issue of
safety of beef. The Committee discussed a draft letter to the CMO.
It was decided that in the present state of knowledge, it was not
thought justified to state categorically that there was no risk
to humans and that it was not appropriate to insist on a zero risk.
|
|
|
|
The
Committee recommended additional attention should be directed at
abattoir methods, in order to minimise cross-contamination of meat
with banned offal.
|
|
|
|
The
Committee discussed the implications of the reported case of feline
SE. Three possibilities were identified: (a) a feline disorder with
no association with BSE or scrapie; (b) feline scrapie; or (c) feline
BSE. The Committee felt it premature to draw conclusions without
further data. The HSE was alerted to the potential for exposure
to cat nervous tissue in neurophysiologists and others. Information
was also sought on the potential for cross-species transfer in veterinary
products.
|
|
|
|
The
Committee recommended strengthening the regular membership of the
Committee with a human neuropathologist.
|
|
|
|
It
was recognised that the Committee's role was to assess scientific
data and opinions as objectively as possible, then to set down judgements
on these in writing. It was important to communicate the message
that science was not absolute and it was for policy-makers to decide
what measures to adopt. The Committee agreed that all advice would
go to MAFF and DH in the first instance with the assumption that
it would be made publicly available.
|
|
|
|
The
Committee requested further information on the theory that the epidemic
would die out if transmission were from cow to calf only, and whether
horizontal transmission (including disposal of placentae) was a
more important problem.
|
|
|
|
The
Committee considered the question of possible human health implications
in the recent discovery of a SE in three cats. They felt that there
was still no way of knowing whether the condition was a previously
unrecognised species-adapted encephalopathy, feline scrapie, or
a BSE-related disease. The Committee agreed it was in no position
to offer advice on the implications for human health until more
was known about the condition. The Committee recommended urgent
research work.
|
|
|
|
As
with the cat, it was too early to recommend action regarding the
appearance of SEs in other animals. The Committee noted that its
views on the safety of beef did not rely on the species susceptibility
of BSE.
|
|
|
|
The
Committee was asked to look at the issue of ruminant feed. The Committee
recommended further study on the issue of feeding ruminant feed
to pigs and poultry. Particular points to be considered were: (a)
pigs had continued to receive the same exposure to the BSE agent
in cattle; (b) most pigs were slaughtered before the likely expression
of the disease; and (c) if pig offal were used in MBM production,
the possibility of the agent being recycled back into cattle was
small.
|
|
|
|
The
Committee was asked by MAFF to consider a paper on slaughterhouse
practices. They recommended that the removal of bovine brains before
head meat was harvested should not be permitted. Similarly, the
same principle of avoiding contamination arose with procedures involving
the spinal cord. Further information was requested on this practice.
|
|
|
|
The
Committee observed that the methodology that had been applied to
the CVL's modelling remained obscure.
|
|
|
|
The
Committee noted that MAFF was willing in principle to fund transmission
experiments with the brains of infected cats.
|
|
|
The
Committee considered that the DH and CVL libraries should undertake
literature searches on behalf of the Committee.
|
|
|
|
The
Committee felt one of its objectives was to produce 'opinions' that
set out clearly what was implied by scientific knowledge. It was
for others to decide what policy decision should flow from this.
These opinions could be backed up by more detailed notes setting
out their scientific basis.
|
|
|
|
The
draft letter to the CMO was agreed, and the longer supporting paper
requested to be circulated for final clearance.
|
|
|
|
The
Committee noted there continued to be no evidence of cattle-to-cattle
transmission either in the field or experimentally.
|
|
|
|
The
Committee noted MAFF was preparing a paper on practices relevant
to BSE, and agreed that a visit to a plant by members was necessary.
|
|
|
|
The
Committee was asked to look at the question of the use of bovine
eyeballs in schools. They agreed with the paper from DH and advised
that the eyes of cattle over six months of age should not be used
for dissection in schools.
|
|
|
|
The
Committee requested that MAFF produce a paper on the implications
of the possible modification of the scrapie agent and on BSE in
the sheep population.
|
|
|
Overview
of developments in research
|
Concern
was expressed about the complexity of arrangements being set up
to coordinate research work, and the MRC would be advised of the
importance of streamlined mechanisms. The secretariat reported Government
discussion on the possibility of an expert to oversee the coordination
of Government-sponsored research.
|
|
|
|
The
Chairman reiterated that there were still questions to be answered
about the analysis of the data collected on the epidemic by the
CVL. It was considered sometimes difficult to judge whether alternative
scenarios to those advanced by the CVL had been adequately tested.
|
|
|
|
The
Committee approved its report produced from a previous meeting on
the intracerebral transmission of BSE to a pig. The Committee recommended
that pigs should no longer be fed with protein derived from SBO.
It was also thought sensible to extend this prohibition to feed
for all species.
|
|
|
|
The
Committee recommended that the cost of funding clinical examination
of cats should be met by public funds to encourage owners to cooperate.
Although the Committee did not believe the disease in cats was of
direct relevance to human health, it needed to be properly investigated
to clarify the nature of the agent that caused it.
|
|
|
|
The
Committee was asked to look at processes employed within the rendering
industry. Questions about the rendering process emphasised the importance
of maintaining monitoring of the outbreak: had it been clearly demonstrated
that the food-borne source of the outbreak had now been cut off?
The Committee advised that experimental work be continued and that
the use of tallow in animal feed be considered.
|
|
|
|
The
Committee noted that a study of archived sheep scrapie brains had
revealed only one case with a neuropathology similar to BSE.
|
|
|
|
The
Committee clarified that MAFF should provide free histological examination
of brain samples from suspect cases but that this did not extend
to the initial clinical examination.
|
|
|
Overview
of developments in research
|
The
Chairman reported approaches from MAFF suggesting the Committee
should have the role of taking an overview of all Government-funded
research into SEs. Concern was expressed that the members of the
Committee did not have the time to do the job properly.
|
|
|
|
Differences
between the BSE agent and scrapie had been demonstrated by:
-
the transmission of scrapie from greyface sheep to mice, which had
shown a longer incubation period than BSE;
-
BSE had been transmitted to a negative-line sheep for scrapie.
|
|
|
|
It
was recorded that BSE had been transmitted both intracerebrally
and orally to sheep.
|
|
|
|
The
Committee welcomed the modelling set out by the NPU comparing the
effect of culling and not culling the offspring of cattle. Although
this might not provide an accurate forecast, it was a useful approach
for identifying key variables. The Chairman felt it would be helpful
to see more of the basic data and detailed workings of the CVL and
NPU lying behind some of the conclusions drawn. The Committee were
concerned that basing hypotheses about the course of the disease
only on cases reported early put a question mark against some conclusions
(and noted that if the BSE agent had changed over time this could
undermine the value of offspring experiments using only material
derived from early cases).
|
|
|
|
A
paper from MAFF tabled at the meeting noted the theoretical possibility
that some slaughtering practices could involve contact between the
spinal cord and meat destined for human consumption. Having asked
the Committee for advice on the subject some members visited a slaughterhouse.
The Committee concluded that, provided all the rules were properly
followed and supervised, there was no need to recommend further
measures on the grounds of consumer protection. In particular, it
was noted that the spinal cord could be extracted from the carcass
without difficulty.
|
|
|
|
Subsequent
to enquiries from MAFF, the Committee did not feel that there was
an urgent need to consider any risks associated with the use of
tallow. However further information was requested on that derived
from cattle and scrapie-infected sheep. A MAFF paper tabled at the
meeting noted that between 30 - 40 per cent of all tallow was used
in animal feed
|
|
|
|
It
was observed that a new EC directive on trade in sheep and goats
required that scrapie should be notifiable. The Committee felt that
it was particularly important that a focused investigation of the
prevalence of scrapie should be undertaken - in advance of the data
yielded by notification.
|
|
|
|
The
Committee was reassured by MAFF evidence that the protein content
of tallow was very low and that MAFF did not believe that tallow
derived from SBOs was likely to reach the food chain. The Committee
requested further information about the real scope for leakage of
such material into human food. On the basis of the available evidence,
it was not thought appropriate to offer specific advice on tallow.
|
|
|
Non-food
uses of bovine material
|
The
Committee requested a note on the use of bovine material in non-food
preparations such as cosmetics.
|
|
|
Disposal
of carcasses and SBO material
|
Noting
the article by Brown/Gajdusek on the survival of the scrapie agent
in soil, the Committee advised that it was not advisable to bury
fallen cattle near the surface, where they could be exposed again.
Concern was expressed over the decline of the service operated by
knackers, which might lead to an increase in this risk.
The
Committee also recommended that on balance it would be better not
to use material derived from SBO as a fertiliser, but that the practice
would be acceptable if the material were subject to more rigorous
heat treatment (ie to the standard for dealing with the CJD agent).
Less caution was needed in Northern Ireland because of the much
lower incidence of BSE and the fact that any infected material would
be diluted considerably.
|
|
|
|
The
Committee reviewed a MAFF paper and concluded that, as there was
no evidence that blood carried detectable infectivity, spreading
bovine blood on agricultural land carried with it no extra risk
of distributing the BSE agent so long as existing controls were
properly applied in the slaughterhouse to ensure that blood was
not contaminated with other tissues.
|
|
|
Overview
of developments in research
|
The
Committee considered that there was an important coordination job
to be done but that it did not have the resources to get a first-hand
view of the work. Cross-representation with other committees and
occasional seminars was felt to provide a workable approach.
|
|
|
Disposal
of carcasses and SBO material
|
The
Committee considered a note tabled by MAFF on the use of heat treatment
similar to that required to neutralise the CJD agent which could
reduce the amount of BSE agent present. It was however concluded
that it could not be guaranteed that material subjected to the heat
treatment would contain no agent. Experimental work could provide
more data on the subject.
|
|
|
|
The
Committee considered the short draft protocol for the milk transmission
experiment. It generally felt that the detail of the experiment
required further consideration, the prime reason for doing the work
being to determine by the most sensitive means whether infectivity
could be conveyed in milk. It concluded that a field study comparing
the pattern of the disease in beef and diary herds would be the
most useful approach. Another would be to orally expose calves with
the milk of affected cows.
|
|
|
Overview
of developments in research
|
Arrangements
for consultation and coordination were becoming established. The
Committee's role fell short of the unified expert guidance that
would exist with a directed programme but this was not felt to be
a realistic approach to pursue.
The
Committee concluded that it would be happy to invite observers from
the Research Councils to participate in relevant discussions but
it did not want to see the permanent membership of the Committee
expanded.
|
|
|
|
The
Committee noted that the possibility that the animal identified
as born after the ban had been fed on ruminant protein could not
be fully ruled out. However, this would not alter the Committee's
view of the disease and the advice that had been offered. This was
due to a lack of similar cases in the field and no positive results
in the offspring study.
|
|
|
Non-food
uses of bovine material
|
The
Committee requested from MAFF a list of non-food uses of bovine
material that had been drawn up in consultation with the slaughtering
industry. It also suggested the advisability of seeking from the
cosmetics industry an indication of whether it used bovine material.
|
|
|
Overview
of developments in research
|
The
Committee emphasised that although contacts had improved with the
AFRC, it was important that the attendance of AFRC representatives
at SEAC meetings were restricted as was consistent to their need
for information.
The
AFRC had discussed organising workshops discussing research into
SEs. The Committee thought that the AFRC should be encouraged to
look into allowing the attendance of non-AFRC funded workers/bodies
to any such workshops.
|
|
|
|
MAFF
had reported that it thought the best approach to the transmission
experiments was to feed milk to mice. The Committee agreed that
this was the best course of action.
|
|
|
|
The
Committee requested progress reports on the contacts established
following the epidemiology seminar in February with the London School
of Hygiene and Tropical Medicine, and on the publication of the
mathematical modelling of the epidemic.
The
Committee requested information on whether contact lens care products
were covered by the Committee on the Safety of Medicines' guidelines.
Also whether any SBOs going for industrial use were likely to end
up in products which might come into contact with human tissues.
|
|
|
|
The
Committee emphasised the importance which it attached to a properly
constructed study of the condition in cats. The species was probably
the animal with the highest level of human contact.
|
|
|
Preparation
of SEAC's Second Interim Report
|
The
Committee felt that three questions needed to be addressed in the
Second Interim Report - (a) had the recommendations of the First
Interim Report been implemented; (b) did the scientific evidence
support the action being taken by HMG; and, (c) were there gaps
in the scientific work or scope for better coordination?
|
|
|
|
The
Committee commented on the three CVL draft papers on the spread
of the epidemic and emphasised the great importance of prompt publication
of these and other scientific papers.
|
|
|
Overview
of developments in research
|
The
Committee had been invited to consider a transgenics research proposal
from St Mary's Hospital. The proposal had previously been turned
down for funding by MAFF and had been further proposed to the AFRC.
While concluding that it did not support the application, the Committee
recognised the importance of work in this emerging field.
The
Committee noted that the AFRC were prepared to widen the participants
of their workshops for discussion of SEs to non-AFRC members.
|
|
|
|
The
Committee noted the two articles describing SEs in ostriches. It
noted that transmission experiments involving tissues from the affected
birds were in hand in Germany. It suggested that consideration
should be given to alerting veterinary surgeons handling zoo animals
of the need to look out for suspicious symptoms.
|
|
|
|
Concern
was expressed over the lack of progress made on work with cats and
that the Bristol research project had not yet received financial
support. The Committee discussed the reservations held in some quarters
over the scientific merits of work undertaken at Bristol and that
this could be the reason it was struggling to attract funding. It
was agreed that the Committee would not assess proposals for research
and that proposals for funding should be routed through the AFRC
research grants board.
|
|
|
Overview
of developments in research
|
The
Committee welcomed the AFRC decision to allow other research teams
to participate in its workshops.
The
Committee discussed correspondence with St Mary's Hospital, confirming
its previous decision not to support St Mary's transgenics research
project.
It
acknowledged the transgenic approach as valid but stated that it
was concerned about the scale of the project and its overlap with
work in progress and planned.
The
Committee reviewed the results of the decontamination of the CJD
Agent experiment. It felt the results were interesting but did not
in themselves give grounds for a change in existing DH guidance
on decontamination of the CJD agent. It felt further work should
be done on quantitative studies.
|
|
|
|
The
Committee requested an analysis of monthly epidemiological data
for future meetings showing any trends which might indicate the
way the BSE epidemic was developing.
|
|
|
Communication
with Lamming
|
The
Committee made it clear that whilst happy to help the Lamming group
by providing its views on particular issues, it did not want to
participate in producing an agreed report. The right procedure would
be for Lamming to make its recommendations and for the Departments
to consider whether these required action by other advisory groups
such as SEAC.
|
|
|
|
The
Committee reviewed the proposed study into SE in cats at Bristol.
The AFRC had initially been prepared to fund the study but this
had been aborted as a result of MAFF's refusal to provide BSE material
for inoculation into cats. The Committee requested that MAFF reconsider
its refusal to do so.
|
|
|
|
The
Committee considered the scope for further work in order to fulfil
its remit to maintain an overview of research. It was clear that
adequate machinery was in place but the Committee emphasised the
need to keep abreast of developments in research across the whole
field of SEs and to consider whether it would be helpful to draw
attention to the wider implications of results.
|
|
|
Overview
of development in research
|
The
Committee discussed the Report of the visiting group to the CVL
epidemiology department. The Committee welcomed the Report's emphasis
on the importance of epidemiological work and its approval of the
high quality of work at CVL.
The
Committee were convinced of the crucial importance of documenting
the diagnoses in those cases found not to be infected with BSE,
and welcomed the proposed detailed study of 1,500 suspect cases
per year, of which a proportion would be not be confirmed as BSE.
|
|
|
Feeding
porcine MBM to cattle
|
The
Committee considered that porcine material was not being fed to
cattle and that it was advisable for that position to continue.
|
Overview
of developments in research
|
The
Committee considered further research on pigs. It felt it was theoretically
possible that pigs could be carrying the agent of BSE or scrapie.
It would therefore make sense to design an experiment to expose
pigs to massive doses and to assess the presence of signs in the
CNS.
|
|
|
|
The
Committee concluded that all the evidence continued to suggest,
in the case of BABs as in earlier ones, that infected feed was the
origin of infection and that there was still no evidence of any
alternative source.
|
|
|
CJD
in farmers and young people
|
The
Committee concluded that DH would look at what needed to be done
to ensure that funding was available for follow up laboratory studies
of Dr Will's study into CJD in a cattle farmer.
|
|
|
|
The
Committee considered recent findings on maternal transmission and
concluded that further investigation was required.
|
|
|
|
The
Committee was asked to review its position on the production of
tallow. It concluded that even though the risk that the presence
of infectivity was slight, it noted that tallow derived from SBOs
was excluded from human food. It would therefore make sense to bring
the rules about the use of tallow for animal consumption into line
with those that applied to human consumption.
|
|
|
|
The
Committee looked into the use of gelatine in the pharmaceutical
process. The Committee noted that for technical reasons spinal cord
was not likely to be included in the raw material of gelatine manufacture.
As long as brains were excluded from the manufacturing process,
the risk that agent might be present in gelatine was negligible.
It
was however necessary to identify potentially hazardous routes,
such as material used for injection or implantation, which merit
more serious consideration than that taken orally. Bovine material
used in the manufacture of gelatine for such purposes should exclude
specified offal, as well as skulls and vertebrae.
|
|
|
|
The
Committee noted that MAFF had agreed to make BSE material available
to Bristol University for the study of FSE, subject to their approval
of the detail of the experiments in which it was to be used.
|
|
|
|
The
Committee considered the infectivity studies of tissues from the
London Zoo kudu. The Committee did not believe that the apparent
high susceptibility of kudu was relevant to BSE in cattle.
|
|
|
|
The
Committee concluded that there was no evidence to suggest that milk
was a hazard to animals or man and no further measures were necessary
to protect public health.
|
|
|
|
The
Committee noted that Ministers had accepted their advice on tallow.
|
|
|
|
The
Committee supported the proposed case control study on BABs aimed
at establishing what, if any, factors beside feed were involved
in those cases.
|
|
|
Disposal
of carcasses and SBO material
|
MAFF
had sought the Committee's endorsement of incineration as the Government's
preferred method of disposal. The Committee agreed that incineration
was preferable to burial.
|
|
|
|
The
Committee recommended that the Institute of Zoology gave researchers
access to greater kudu tissues to study the basic biology of the
species in relation to others and try to establish why these animals
appeared to be more susceptible to SE.
|
|
|
Overview
of developments in research
|
The
Committee considered a paper on Dr Narang's research proposal into
a diagnostic test for the live animal and agreed that it was necessary
to have independent corroboration of his findings.
The
Committee also emphasised the importance of defining bovine brain
disorder in detail with transmission studies and PrP examination.
The
Committee agreed that after the ACDP working Party on SEs had produced
their guidelines on occupational risk, it would take on the responsibility
for considering the occupational risks involved in SEs.
|
|
|
CJD
in farmers and young people
|
The
Committee reviewed the evidence of the case of CJD in a farmer.
They agreed that biological characterisation of the agent needed
to be carried out as a matter of urgency. Also that if a third case
of CJD in a farmer with BSE in their herd occurred, an immediate
full Committee meeting would be required.
|
|
|
|
The
Committee considered the paper on hormone extracts from Professor
Lamming on behalf of the Veterinary Products Committee. It was agreed
that there were no reasons to worry about the particular material
proposed but that the question of risk acceptance by consumers should
be considered. The Committee agreed that the reply to Professor
Lamming would be drafted along those lines with a proviso stating
that it was given in light of present knowledge and that new information
coming to light may alter the advice given.
|
|
|
|
The
Committee was disturbed that the feed ban had not been as effective
as early as hoped. It was recognised that the level of infectivity
in MBM produced before the ban was still increasing due to recycling
of bovine material and it was obvious that compounders and farmers
had taken longer to use this material than expected. Information
on cases in the group born in 1990 would be critical.
|
|
|
|
The
Committee commented on the most recent study and it was agreed on
the information presented that the number of cases seen in the progeny
of cases were not different from those seen in the population as
a whole. It was appreciated that it was still possible that alternative
routes of transmission might emerge as the epidemic continued.
|
|
|
|
It
was suggested that a Deputy Chairman was required. Dr Will
was proposed and the proposal was agreed.
|
|
|
SEACs
Second Interim Report
|
The
Committee made detailed comments on the report. It was agreed that
the top priority in producing the report should be quality rather
than speed.
|
|
|
|
The
Committee's attention was drawn to a possible problem concerning
tallow from SBOs, which had come to light in recent discussion between
MAFF and the industry. The Committee reviewed the situation regarding
tallow. They requested more information on the process which was
allowing tallow into animal feed through the oleochemical industry
process.
|
Emergency
Meeting 25/6/94
|
Advice
on thymus and intestine of calves
|
The
Government asked for the Committee's advice on the infectivity of
distal ileum of calves under six months of age. The study indicated
that there was infectivity present in BABs. This suggested that
the exemption of SBO from calves under six months was perhaps inadvisable.
The
Committee, however, thought that the risk to human health from food
derived from infected calves was minuscule if it occurred. It concluded
that the experiment should be closely monitored to see whether further
action was required.
|
|
|
Advice
on thymus and intestine of calves
|
The
Committee noted that the Government response to the findings discussed
on 25 June went beyond what SEAC considered scientifically appropriate.
|
|
|
The
Committee expressed its disappointment with the lack of progress
with the transmission studies into the two dairy farmers who had
CJD.
|
|
|
CJD
Surveillance Unit's Third Annual Report
|
The
Committee were asked to consider the latest report, in particular
the significance of the finding that the consumption of veal could
be a risk factor for CJD. The Committee considered the Report and
thought that clear progress had been made. However, certain areas,
such as that on veal, could be taken out of context and therefore
redrafting would be prudent. The Committee agreed a statement which
could be used by DH when the report was published. It also agreed
that it had no new advice to give the Government on the basis of
the Report.
|
|
|
|
The
Committee considered the maternal transmission study. It was agreed
that more work was needed in the area. Possible areas of consideration
could include the possibility of change in the agent, differential
diagnosis and the implementation of the feed ban.
|
|
|
|
The
Committee were asked by MAFF to reconsider the evidence on the use
of tallow in the oleochemical industry. The industry thought that
the processes used would be successful in inactivating the BSE agent.
The Committee agreed that the risk from the SBO tallow fractionalised
by the industry was minuscule if it existed at all. This recommendation
was conditional on the introduction of good monitoring and control
of the end product.
|
|
|
Overview
of developments in research
|
The
Committee reviewed the hound study undertaken by the SVS, as they
had recommended. This was carried out in the form of general monitoring
of domestic hounds and also a specific survey of hound packs. a
The Committee concluded that there had clearly been problems with
it, particularly the control on the histology, and that it was more
or less inconclusive. It was agreed that there should be a re-evaluation
of the pathological material in the study.
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CJD
in farmers and young people
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A
special meeting was called to consider the significance of a third
case of CJD arising in a dairy farm worker. The Committee thought
that more information was needed before firmer conclusions could
be drawn. It agreed that the case did not suggest that there was
any need for Government to revise the measures already taken to
safeguard public health against occupational and other possible
routes of exposure to the BSE agent.
The
Committee felt that a statement reflecting the Committee's assessment
of the situation should be prepared for the DH to use in response
to media enquiries.
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Overview
of developments in research
|
The
Committee strongly endorsed the conclusions of the minutes of the
special meeting and emphasised that transmission studies in mice
and strain typing in mice of isolates from the three CJD cases in
dairy farmers must be given highest priority.
The
Committee considered the proposal to burn SBO-derived greaves at
a power station. The Committee concluded that this process would
be a very good way of disposing of SBO-MBM. The resulting ash would
be buried in approved land-fill sites.
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The
Committee reviewed the latest transmission studies which showed
that infectivity had not been found in any tissues from calves killed
two months after challenge. The Chairman asked whether any representations
had been made as a result of these findings for a relaxation in
the SBO ban. It was felt that it was too early to consider any revision
of the ban.
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The
Committee concluded it was happy about the safety of zoo visitors
but not about the background epidemiology.
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The
Committee considered further evidence of BABS and cross-contamination
of feed. It concluded that there were a number of possibilities
for cross-contamination which appeared to be the main reason for
BAB cases. Epidemiology needed to be continued and reiterated. The
Committee was very concerned that possible contamination of feed
would continue the epidemic.
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The
Committee examined the status of gelatine in the context of Commission
Decision 95/60 of 6 March 95 concerning protection measures with
regard to BSE and the feeding of mammalian derived protein. This
excluded gelatine and blood products from the SBO ban. This had
not been implemented as yet in the UK. The Committee concluded that
in order to agree the exemption for gelatine it needed to be convinced
that a negligible amount of infectivity was present in the raw material.
This was reliant on the adequacy of the SBO control measures.
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The
Committee considered whether the exemption in the Committee decision
of blood and blood products from the SBO ban would represent any
risk and concluded that it did not believe it to be a matter for
concern. It agreed that the exemption from the ban was appropriate.
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The
Committee concluded that, provided in the slaughtering process the
removal of the spinal cord was done properly, the MRM process was
safe and there was no reason for it to change its advice.
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The
Committee reviewed the first case of BSE in an animal born in 1992.
It thought that for contamination of feed to have continued there
must have been failure at three levels: the slaughterhouses, the
renderers and the feed mills.
The
Committee concluded that although it had no further comments on
the BAB case it remained a concern that any problems of control
should be rectified as soon as possible.
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The
Committee was very concerned at the reports of the lack of compliance
in removal of SBOs. The Committee felt that if there was something
going wrong, action should be taken as a matter of highest priority.
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Overview
of developments in research
|
The
Committee reviewed the results of the Idiopathic Brain Neuronal
Chromatolysis study (transmission studies in mice from brains of
two cows with IBNC). It noted that the results were unusual and
thought a suggested line to take would be to say that these were
scientifically unpublishable results but in line with the policy
of openness they would be made publicly available and further work
done to test their validity. Since the BSE precautions were applied
to IBNC cases, human health was protected.
The
Committee reevaluated the hound study to see if any useful results
could be gained from it. The Chairman concluded that there were
varying opinions within the Committee on further work. It did not
suggest any further transmission studies and thought that the lack
of clinical data was a major weakness.
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The
Committee reaffirmed its view that the case of the third farmer
with CJD should be included in the transmission studies - regardless
of cost because of its potential importance.
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The
Committee was content with the exemption from the SBO ban under
EU law for gelatine to be given effect. This was after MAFF confirmed
that with the new SBO Order gelatine could be regarded as free from
SBOs.
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The
Committee discussed that there may have been some leakage of SBOs
into animal feed, prior to the new SBO Order and the revised surveillance
programme, which may have affected the incidences of BSE in cattle
born after the 1990 SBO Ban.
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CJD
in farmers and young people
|
The
Committee reviewed the CJDSU's Fourth Report (August 1995). They
concluded that although there had been an increase in the incidence
of CJD in 1994, it would be premature to conclude that this indicated
an additional risk factor for CJD in the UK.
The
Committee agreed that no conclusive evidence existed of any change
in the incidence of CJD attributable to BSE. However, because of
the long incubation period, the study would need to continue for
a number of years before firm conclusions could be drawn.
The
Committee agreed that the cases of CJD in adolescents should be
studied in great detail and it should consider whether they had
any implications for the cause or management of the disease.
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CJD
in farmers and young people
|
The
Committee was required to comment on the possible fourth case of
CJD in a cattle farmer.
The
Committee concluded that there was a worrying number of cases in
farmers exposed to cattle with BSE. However, if there were an occupational
link, there would be other occupations equally, if not more at risk.
The stage was being reached where it was difficult to explain the
cases as a chance phenomenon. It was unclear whether the potential
risk factor might be association with animals with BSE or the food
given to them. The transmission studies were particularly important.
The
Committee recommended that transmission studies were carried out.
It decided that it would be irrational to take specific measures
at the present time. It issued a statement which DH could use in
response to media enquiries if required.
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The
Committee considered the issue of removal of spinal cord. It reviewed
its previous opinion that, provided the process was carried out
properly, MRM was safe. It decided that in light of recent audit
reports showing failure to remove parts of the spinal cord in a
small number of carcasses its position should change. The Committee
concluded that until it was clear that removal of spinal cord was
being undertaken properly in all cases it would be prudent to suspend
the use of vertebrae from cattle over six months old, in the production
of MRM. It also considered that rib of beef joints were safe.
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The
Committee was asked by DH to look at the risk of transmission through
blood transfusions. The Committee reviewed its position on blood
and concluded that there was no new evidence of risk from blood
suggesting the necessity for new measures, although other EU States
may raise the issue independently.
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The
Committee was asked to comment on the Advisory Note for Farmers
issued by MAFF in 1990 and whether or not it should include advice
not to eat cattle feed. The conclusion was that there was no significant
risk, therefore no specific advice should be included.
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Overview
of developments in research
|
The
Committee agreed that SEAC should seek a neutral critique of Dr
Dealler's article by an independent epidemiologist.
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The
Committee discussed publicity and decided that the minutes of meetings
would remain confidential but individual Committee members were
free to speak on the subject as they saw fit.
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CJD
in farmers and young people
|
The
Committee discussed recent cases of CJD. It concluded that the situation
demanded the continuation on the intensive monitoring of CJD.
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The
Committee had a discussion about MRM and the discovery of spinal
cord attached to carcasses. Concern was expressed by a number of
Committee members on this issue. They felt they needed reassurance
that SBO controls were being carried out properly before they could
maintain their current advice on MRM.
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The
Committee reconsidered the question of blood transfusions. Although
recipients of blood from CJD cases could be traced through and monitored,
the Committee felt that it would be inappropriate to notify them
in view of the very small risk involved in relation to stress caused.
It did however consider it important to record details of blood
donations by patients who die of CJD.
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The
Committee considered a DH paper on scrapie and its link with hGH
CJD cases. It did not feel that it was something which was likely
to be a significant factor. Transmission from humans, with no species
barrier, was the most likely cause of all the hGH derived cases.
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Overview
of developments in research
|
The
Committee considered the scrapie rendering experiment and it was
clear that all systems other than the pressurised German type had
failed to fully inactivate the BSE agent. Although this could be
considered sufficient evidence to advise on policy, it was an EC
funded experiment and would as such be interpreted by the SVC.
The
Committee recommended that Ministers should ensure that the CJDSU
had sufficient funds to allow it to carry on with its epidemiological
studies.
The
Committee discussed research priorities and would consider the projects
paper fully before deciding on priorities. It placed considerable
importance on directing some funds towards new facilities for strain-typing.
Also that it might be useful to commission some further work about
the cause of the epidemic and the explanation for the continuing
number of BABs.
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Advice
on slaughterhouse practices and MRM
|
The
Committee discussed its future visit to a slaughterhouse and the
level of current compliance with SBO controls. Dr Matthews would
produce a paper for the next meeting.
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Overview
of developments in research
|
The
Committee reviewed the bovine transgenic mouse models. It concluded
that scientifically classical panels of mice and transgenic mice
were equally important for surveillance and epidemiological studies
of human and animal TSEs and both need to be adequately resourced
to meet current and future needs.
The
Committee judged that the surveillance and epidemiology of human
and animal disease was of high priority, as was the study of occurrence
and incidence of BSE in the National Sheep Flock.
The
Committee discussed the issue of other research and concluded that
there was a need for continued basic research on TSEs and that Research
Council funding should continue.
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The
Minister required the Committee's views on specific questions that
could be published in the form of a press release.
The
principal questions to be answered were whether beef was safe to
eat. This was entirely dependent on the full implementation of the
SBO regulations. Also whether beef products were safe to eat. This
was answered in the positive as long as SBOs were removed, there
should be no greater risk than from prime beef. It also drafted
responses to the questions of whether the epidemic was in decline
and the cause of BSE.
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Overview
of developments in research
|
The
Committee addressed the critique of Dr Dealler's paper and agreed
to seek yet more neutral critics to review the paper.
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