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From: TSS ()
Subject: BSE AND GOATS SEAC 86/4
Date: February 25, 2005 at 9:32 am PST
SEAC 86/4
1
BSE AND GOATS
Issue
The Department for Environment, Food and Rural Affairs (Defra) and the
Food Standards Agency (FSA) announced on the 8th February 2005 that a UK
goat, confirmed in 1990 as having a TSE presumed on the best available
evidence at the time to be scrapie, may have had BSE (Annex 1). This
announcement was made following preliminary work performed by scientists
at the Veterinary Laboratories Agency (VLA) where immunohistochemistry
(IHC) has been applied to two historical samples.
This follows the recent confirmation of BSE in a French goat slaughtered in
2002 and tested as part of the EU-wide TSE surveillance programme.
Points for Discussion by the Committee
Both Defra and FSA would be grateful for views on this recent development
and more specifically would welcome comments on:-
• Future research needs relating specifically to the possible case of BSE in
a UK goat
• EFSA is currently undertaking a full assessment of the BSE-related risk
associated with the consumption of goat meat and goat meat products. In
relation to the UK, has the Committee any comment on the level of current
risk?
SEAC 86/4
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Background
Possible BSE in a UK Goat
Introduction
Martin Jeffrey at VLA-Lasswade, Edinburgh has developed a
immunohistochemistry (IHC) method to discriminate between BSE and
scrapie in sheep. This method was recently shown to be discriminatory in an
EU evaluation of discriminatory methods, together with two Western
immunoblotting methods and an ELISA based-method. All of these methods
are now recommended for use in the examination of samples that test positive
in the EU-wide surveillance programme for TSEs in small ruminants. The
Community Reference Laboratory’s Expert Group have agreed that none of
the three in isolation is sufficient to confirm the presence of BSE and
all three
need to agree before a sample is confirmed as being indicative of BSE. This
has now been set out in a Commission Regulation1.
Although IHC was not used to evaluate the recent French case of BSE in a
goat, because brain tissue had not been stored in preservative and only
frozen brain material was available which could not be used, the VLA have
considered whether the method could be applied to goats as well as sheep.
To achieve this the VLA examined brain tissue from goats that had been
experimentally infected with BSE or scrapie, and compared them with two
archived brain samples from scrapie-affected goats, namely:-
• Five experimental BSE in goat samples provided by the IAH
• Five SSBP-12 goat samples provided by the IAH (an experimentally
transmitted isolate of scrapie)
• Two historical samples of goat TSE (presumed scrapie) retained at VLA
Lasswade
One of these latter samples, first reported to a veterinary centre in
Scotland in
1990, has given an IHC result which is indistinguishable from the
experimental BSE in goat samples (note – only the one method has been
applied).
Because of the age of the sample the VLA only have fixed material. This
means that they will not be able to perform any of the other molecular
tests,
such as Western blot and ELISA. The only way that this sample can be
confirmed to be from a BSE infection is for some of the fixed material to be
inoculated into mice.
VLA-Weybridge is also retrieving as many goat samples as it can identify
in its
archive to process in a similar fashion. Only eight goat TSE cases have been
confirmed since January 1993 when scrapie became notifiable. None of the
1 Exact details of the Regulation can be found at
http://europa.eu.int/eurlex/
lex/LexUriServ/site/en/oj/2005/l_010/l_01020050113en00090017.pdf
2 Sheep Scrapie Brain Pool 1 (SSBP-1) is a highly characterised pool of
scrapie strains used
by the IAH, which they routinely use in their experimental challenge work.
SEAC 86/4
3
examinations done so far have been sufficiently well peer-reviewed to enable
the results to be reported, but none so far appear to look like BSE.
Herd of Origin
The male goat was born in March 1987 and was sold in May 1988. The
animal was subsequently euthanased in 1990 after showing clinical signs
consistent with scrapie, and the Scottish Agricultural College/VLA-Lasswade
confirmed a scrapie-like infection by histopathological examination of fixed
brain material. The goat was fed oats and barley mix supplemented with
concentrate mix. The originator herd where the animal was bought from is no
longer in existence. The owner of the goat when it developed disease has
since moved the herd to new premises. There are some progeny, up to 6th
generation, of the original goat in the current herd of six or seven
animals but
no further reports or suspicion of neurological or wasting disorders amongst
these animals. No sheep or cattle were present on the holding in 1990 (the
land is now used for non-agricultural purposes) or are present on the
holding
of the current herd. No goat meat, milk or milk products are sold into the
human food chain from the herd.
Surveillance in the UK
In 2002, the European Commission initiated a programme of TSE surveillance
for small ruminants aged over 18 months based on samples collected from
abattoirs and fallen stock. In 2004, the UK was not required to test
goats at
abattoirs but was required to test 500 fallen goats.
Year Numbers Tested Positive
2002 9 0
2003 191 1
2004 90 0
2005 43 0
Abattoir
Total 333 1
2002 3 0
2003 53 0
2004 49 0
2005 1 0
Goat
Fallen Stock
Total 106 0
Results of the abattoir and fallen stock survey
Following the recent confirmation of BSE in a French goat from 2002,
enhanced testing of goats to establish the level of TSEs in the current EU
goat population was agreed in early February. Sample size has been based
on the level of BSE in the member state and the size of its goat population.
The UK will now have to test:-
• all goats aged over 18 months slaughtered for human consumption (it is
estimated that this will be approximately about 3000 goats per annum)
• 1000 fallen goats over 18 months
SEAC 86/4
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If member states have difficulty obtaining their quotas of abattoir samples,
they can substitute additional fallen stock on a one to one basis.
Defra is consulting the goat industry on how best to implement these new
requirements. Defra envisage making it a legal obligation on goat keepers to
notify all fallen goats aged over 18 months. All goats are already being
tested
in 13 abattoirs where sheep are being sampled. This surveillance will be
extended to other key abattoirs as soon as possible but, in view of the
difficulties in testing all goats slaughtered in any abattoir, Defra may
wish to
substitute some additional fallen stock.
UK goat population
The UK census indicates that there are about 88,000 goats, half of which are
breeding animals. In England and Wales there are 30,000 milk producing
goats. The level of goat meat production in the UK is relatively low
with only
7,699 slaughtered in licensed abattoirs in 2003/04. Levels of goat cheese
production in the UK are estimated to be 1,800 tonnes per annum with about
10,000 tonnes of goats milk consumed per annum, in comparison with several
million tonnes of cows milk.
All TSE legislation that applies to sheep also applies to goats (except that
goats do not carry the ARR genotype that confers scrapie resistance to
sheep). This includes the UK feed ban in 1988 and the reinforced feed ban in
1996, and the removal and destruction of specified risk material (SRM). SRM
for sheep and goats is listed in Annex 2.
Confirmed BSE in a French Goat
Background
This goat was born March 2000 and slaughtered in October 2002 when it was
TSE tested as part of the EC requirement for random testing of healthy sheep
and goats. On the basis of initial tests to differentiate BSE and
scrapie it was
decided that strain typing by mouse bioassay was needed. Following an
analysis of these results and from the results of further tests, as
requested by
the Central Reference Laboratory’s Expert Group on TSE strains, the Expert
Group concluded that ‘the French caprine isolate (CH636) is likely to
contain
the BSE strain’. (These tests did not include IHC on the original sample
because no fixed brain tissue was available).
Material from this goat did not enter the food chain. It was one of
total herd of
600 goats (300 adults and 300 below reproductive age), all of which were
slaughtered and tested for TSE. All test results were negative.
No meat or live goats have been imported from France since 1997. The levels
of French goat cheese imported into the UK are uncertain but are not
insignificant.
The goat was tested as part of an EU-wide TSE surveillance programme on
samples collected from abattoirs and fallen stock. Within this programme
SEAC 86/4
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some 140,000 goats (60,000 of which were in France) have been tested, of
which 134 were found to be TSE positive. Thirty of these have been
subjected to discriminatory testing yielding only the one BSE positive from
France.
Statements from the European Food Safety Authority on the finding of
BSE in the French goat
As a result of the November 2004 announcement of the possible finding of
BSE in the French goat and the confirmation of this finding in January 2005
the European Food Safety Authority (EFSA) was asked by the EC to provide
an opinion on the risk posed by goat meat and milk, and products derived
from them. The EFSA opinion of 26/11/04 (Annex 3) concluded that ‘in the
light of current scientific knowledge and irrespective of their geographical
origin, milk and milk derivatives (eg lactoferrin, lactose) from small
ruminants
are unlikely to present any risk of TSE contamination provided that milk is
sourced from clinically healthy animals.’
EFSA also launched a feasibility study to check availability and
usefulness of
existing or new data and to collect information to form the basis for
carrying
out a quantitative assessment of the risks involved in the consumption
of goat
meat and goat meat products. The responses to this were discussed at a
working group meeting on this subject on 11/01/05. It is hoped that this
risk
assessment will be completed by July 2005.
In a further statement on 28/01/05 (Annex 4) EFSA recognised that there are
significant gaps in the knowledge needed to carry out a quantitative risk
assessment. In particular the data on consumption of goat meat and products,
the prevalence of natural BSE in goats and the distribution of
infectivity in goat
tissues.
SEAC advice
SEAC’s previous consideration of risks should BSE be found in small
ruminants is given in Annex 5.
SEAC 86/4
Annex 1
6
Nobel House
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London SW1P 3JR
Telephone 020 7238 1134
Fax 020 7238 5529
Out of hours telephone 020 7270 8960
Out of hours fax 020 7270 8125
Website www.defra.gov.uk
News Release News Release ref : 58/05
Date: 8 February 2005
POSSIBLE BSE IN A 1990 UK GOAT SAMPLE
Scientists at the Veterinary Laboratories Agency have informed Defra that a
goat, confirmed as having scrapie in 1990, may have had BSE.
More sensitive testing methods have found the sample had traits similar to
samples from goats experimentally infected with BSE. Further tests will now
be carried out.
The VLA made the finding following the recent case of BSE in a goat from
France. The VLA had been checking whether methods developed to
discriminate between scrapie and BSE in sheep could also differentiate these
diseases in a goat.
The goat appears to have originated from premises in Scotland;
investigations
have revealed that the original keeper is no longer in business at these
premises.
The single result, using just one test method, is insufficient to
confirm that the
goat had BSE, and further rapid molecular methods to discriminate BSE and
scrapie cannot be applied because no frozen tissues are available.
Researchers from the VLA have been asked to carry out tests to follow up
these initial findings. Further work will now need to be performed and
this will
take 1-2 years, at the earliest, to complete.
SEAC 86/4
Annex 1
7
Defra’s Chief Veterinary Officer, Debby Reynolds, said: “It is important
to put
this initial finding into context. It dates back to 1990 which was at
the height
of the BSE outbreak in cattle and before the reinforced feed ban was
introduced in 1996. This means that there is a distinct possibility that the
animal, if infected with BSE, was exposed to contaminated feed.
“In light of the recent case of BSE in a goat from France, the European
Commission says it is important to perform increased surveillance on
goats on
a European-wide basis to establish the current incidence of TSEs in the goat
population. In line with this, Defra will be stepping up its TSE
surveillance
programme for goats.”
Defra will be asking the Spongiform Encephalopathy Advisory Committee for
their comments on this finding at their meeting on the 3rd March.
NOTES TO EDITORS
1. Further details about the case of BSE in a French goat detected in 2002
can be found on the European Commission’s web site at:-
http://europa.eu.int/rapid/pressReleasesAction.do?reference=IP/05/105&fo
rmat=HTML&aged=0&language=EN&guiLanguage=en
2. More details concerning the feed ban is available on the Defra web site:-
http://www.defra.gov.uk/animalh/bse/controls-eradication/feed-ban.html
3. General information relating to BSE can be found at:-
http://www.defra.gov.uk/animalh/bse/index.html
4. General information relating to scrapie can be found at:-
http://www.defra.gov.uk/animalh/bse/othertses/scrapie/index.html
Press enquiries 020 7238 6094 ;Public enquiries 08459 335577;
Press notices are available on our website
www.defra.gov.uk
Defra’s aim is sustainable development
End
SEAC 86/4
Annex 1
8
Possible finding of BSE in a 1990 UK goat
Agency not advising against eating goat meat or dairy products
Tuesday, 08 February 2005
Ref: R1076 - 38
The FSA has been informed by Defra that a sample, reportedly taken from
a Scottish goat (1) that died in
1990, has shown that the goat may have had BSE (2). Archived tissues
from this animal were recently
tested by Defra’s Veterinary Laboratory Agency but confirmation of BSE
requires further tests and these
will take up to two years.
Few if any goats from 1990 are likely to still be alive today and BSE
has not been found in the current UK
goat population. It may be possible for BSE in goats to pass down
through the generations and the current
precautionary controls would not remove all infectivity from the goat
meat were the animal to enter the food
chain. However, animals that show visible signs of TSEs (3), which
includes BSE, are not permitted to
enter the food chain.
If confirmed, this Scottish case would be the second goat to test
positive for BSE, following confirmation on
28 January 2005 that a French goat that died in 2002 had BSE. Since
2002, 140,000 goats have been
tested for TSEs across Europe and no cases of BSE have been identified,
except for the French case. The
European Commission is stepping up the goat-testing programme to
determine whether this is an isolated
incident.
There is scientific uncertainty in this area. However, the most recent
advice (4) on dairy products from the
European Food Safety Authority (EFSA) states that milk and milk products
from goats are unlikely to
present any risk of TSE contamination provided the milk is sourced from
healthy animals, irrespective of
country of origin. EFSA is continuing to work on a risk assessment in
relation to goat meat. The Agency will
also be seeking scientific advice from its own independent experts SEAC
(5). There have been no goat
meat imports from France into the UK since 1997.
On the basis of the current evidence, the Agency is not advising people
against eating goat meat or
products, including dairy products.
The Scottish goat died six years before a full ban on the use of
potentially BSE infected feed to farmed
animals was introduced in the UK in 1996. This ban was subsequently
extended across Europe in 2001.
The ban prevents the spread of BSE infection to animals through feed.
The Agency is working closely with the European Commission and other
member states to consider what
further action may be required in the light of the results of increased
testing.
The Agency will issue further information and advice as appropriate.
Footnotes
(1) VLA is looking to conduct further tests to confirm that the sample
tissue is from a goat.
(2) Defra press release can be found at Defra's website
(3) TSE, Transmissible Spongiform Encephalopathy, is a disease of the
neurological system where there is
spongy degeneration of the brain and progressive neurological
deterioration. Scrapie is a TSE that is
known to infect sheep and goats. BSE, which affects cattle, is also a
TSE. Goats showing signs of TSEs
are not permitted to enter the food chain.
(4) EFSA advice can be found at the EFSA website
SEAC 86/4
Annex 1
9
(5) SEAC – the Spongiform Encephalopathy Advisory Committee – was set up
in 1990 and provides
independent scientific advice to the Food Standards Agency and other
Government Departments on BSE
and other spongiform encephalopathies.
BSE and goats – your questions answered
[ENDS]
Room 245 Aviation House,
125 Kingsway,
London WC2B 6NH
Telephone: 020 7276 8888
Out of hours duty pager: 07626 414243
Fax: 020 7276 8833
Email: press.mailbox@foodstandards.gsi.gov.uk
© Crown Copyright
SEAC 86/4
Annex 2
10
Specified Risk Material
Cattle born, reared and slaughtered in the UK
All ages
• The tonsils and intestine from the
duodenum to the rectum; and the
mesentery;
Over 6 months
• The entire head (excluding the tongue, but
including the brain, the eyes, trigeminal
ganglia), thymus, spleen and spinal cord.
Over 30 months
• The vertebral column, excluding the
vertebrae of the tail, the spinous and
transverse processes of the cervical,
thoracic and lumbar vertebrae and the
median sacral crest, the wings of the
sacrum, but including the dorsal root
ganglia.
- in the UK this only applies to Beef
Assurance Scheme animals, all other cattle
over 30 months of age are excluded from
the food chain.
Cattle all member states except UK
All ages
• The tonsils, the intestines, from the
duodenum to the rectum, and the
mesentery;
Over 12 months
• Skull excluding the mandible but including
the brains and eyes, and spinal cord .
Cattle (in all Member States except UK and
Sweden)
Over 12 months
• Vertebral column, excluding the vertebrae
of the tail the spinous and transverse
processes of the cervical, thoracic and
lumbar vertebrae, the median sacral crest
and the wings of the sacrum, but including
the dorsal root ganglia .
Sheep and goats (applies to UK and all other
Member States)
All ages
• The spleen and the ileum
Over 12 months (or with a permanent
incisor erupted)
Skull including the brains and eyes, tonsils,
spinal cord.
SEAC 86/4
Annex 3
11
Page 1 of 1
European Food Safety Authority
Brussels, 26 November 2004
Statement
of the EFSA Scientific Expert Working Group on BSE/TSE
of the Scientific Panel on Biological Hazards
on the health risks of the consumption
of milk and milk derived products from goats
The former Scientific Steering Committee of the European Commission and
recently
the European Food Safety Authority (in its opinion related to TSE
surveillance and
product safety in small ruminants) have recommended that research should
intensify
on the safety of milk of small ruminants with regard to TSE risks.
Despite these
repeated recommendations there is very limited published research data
on TSE in
goats and infectivity of goat products. Although limited new data are
expected to be
published in the near future, there is still little research initiated
in this area.
Some research data support the finding that milk, colostrum and tissues
of the
mammary gland from bovines can be classified in the category of no
detectable
infectivity. However, based on a number of observations from research
data, mainly
research concerning sheep, there are indications that infectivity in the
milk from
small ruminants cannot be totally excluded. In case of mastitis, one
could expect an
infiltration of potentially infected blood into the milk as the
blood-milk barrier may not
or only partly exist. But even in the case of absence of mastitis the
barrier may not
be 100% effective.
From the limited data available today it is concluded that in the light
of current
scientific knowledge and irrespective of their geographical origin, milk
and milk
derivatives (e.g. lactoferrin, lactose) from small ruminants are
unlikely to present any
risk of TSE contamination provided that milk is sourced from clinically
healthy
animals. Exclusion of animals with mastitis is considered to reduce the
potential risk.
Further assurance of healthy milk could include milk tests for total
somatic cell
counts indicative of inflammation.
12
SEAC 86/4
Annex 4
European Food Safety Authority
SCIENTIFIC PANEL ON BIOLOGICAL HAZARDS
Brussels 28 January 2005
Statement on the assessment of safety with respect to the consumption of
goat meat and
goat meat products in relation to BSE/TSE”
Following the findings of a research group in France concerning a
suspected case of Bovine
Spongiform Encephalopathy (BSE) infection in a goat, EFSA was asked by
the Health and
Consumer Protection Directorate General (DG SANCO) of the European
Commission, and
subsequently by the European Parliament, to provide scientific advice on
the human health risks
related to the consumption of goat milk and goat meat. This case,
identified as a TSE in a normal
slaughter goat in the course of active surveillance in 2002, was
confirmed by subsequent
molecular phenotyping and a two-year bio-assay as indistinguishable from
a BSE infection.
EFSA’s Scientific Panel on Biological Hazards (BIOHAZ) undertook to
update previous opinions
related to risks associated with the consumption of goat and sheep
products in the event that
BSE were to be confirmed in the goat concerned. In light of the
conclusions of the Community
Reference Laboratory’s expert panel confirming the presence of BSE
infection in the goat
(http://europa.eu.int/comm/food/food/biosafety/bse/crl_statement_tse_goats_28-01-05_en.pdf)
the BIOHAZ Panel outlines the current state of knowledge and affairs
concerning the assessment
of BSE-related risks with respect to the consumption of goat meat and
goat meat products.
With regards to possible health risks associated with the consumption of
milk and milk products
derived thereof, EFSA’s Scientific Expert Working Group on BSE/TSE of
the BIOHAZ Panel
published preliminary advice on 26 November 2004
http://www.efsa.eu.int/science/biohaz/biohaz_documents/709/bdoc_statement_goatsmilk_en1.pdf
. Experts agreed that: “…in light of current scientific knowledge and
irrespective of their
geographical origin, milk and milk derivatives (eg lactoferrin, lactose)
from small ruminants are
unlikely to present any risk of TSE contamination provided that milk is
sourced from clinically
healthy animals.” .
With regards to the provision of scientific advice related to the safety
of goat meat and goat meat
products, and following a feasibility study, the BIOHAZ Panel confirmed
that significant gaps exist
in the information required to carry out a quantitative risk assessment
with regards to BSE/TSE.
In particular, the Panel highlighted the absence of information
regarding consumption of goat
meat and goat meat products and other data required to assess exposure,
particularly the true
prevalence of BSE infection in goats under natural conditions and the
distribution of infectivity in
goat tissues.
From the epidemiological data available today, no link is indicated
between goat meat and meat
product consumption and variant Creutzfeldt Jakob Disease (vCJD).
However, the BIOHAZ Panel
recognises the lack of knowledge with respect to the incubation period
of vCJD and exposure
levels of the human population which limits confidence in this observation.
The advice on safety of goat products as concluded in the opinion of the
Scientific Steering
Committee (SSC) opinion of April 2002 on “Safe sourcing of small
ruminants’ material” and
reiterated by the Opinion* of the Scientific Panel on Biological Hazards
of the European Food
Safety Authority on “The interpretation of results of EU surveillance of
transmissible spongiform
encephalopathies (TSEs) in ovine and caprine animals, culling strategies
for TSEs in small
ruminants and the TSE-related safety of certain small ruminant products”
adopted on 26
13
November 2003, remains valid. However, the BIOHAZ panel and further
recognises that more
information is needed to assess the significance of the single French
case recognizes the need to
carry out a quantitative risk assessment concerning BSE-related risks
associated with the
consumption of goat meat and goat meat products. This is expected to be
completed by July
2005 if pertinent data will become available.
* ”The current document might be appropriately updated when
..~….reliable data on the
prevalence become available”.
1. Background
Following the earlier announcement of a suspected case of BSE infection
in a goat (28 October
2004) and the preliminary and final confirmation by the Community
Reference Laboratory (CRL),
on 25 November 2004 and 28 January 2005 respectively, and taking into
account the formal
mandate from the Health and Consumer Protection Directorate General of
the European
Commission (DG SANCO) (D(2004) DS/cm/421319) of the European Commission
requesting
EFSA’s Scientific Panel on Biological Hazards for an opinion on a
“Quantitative assessment of
risk posed to humans by tissues of small ruminants (SMRU) in case BSE is
present in
these animal populations” and a similar mandate from the European
Parliament (EP) (letter
314273 of 21.12.2004), the following update on the state of play is
provided.
Overview of actions taken by EFSA
EFSA launched a series of actions following the announcement by the
French Authorities
of a suspected case of BSE infection in a goat. These actions focused on
the collection of
scientific data and other information from scientists as well as from
food safety authorities
and research institutes in Member States in order to be able to carry
out a quantitative risk
assessment with regards to the possible risks involved in the
consumption of goat
products should a BSE infection be confirmed.
1. A feasibility study was launched on 30 October 2004.to check the
availability and usefulness of
existing or new scientific data and to collect other information as the
basis for carrying out a
quantitative assessment of the risks involved in the consumption of goat
products.
2. Questions were sent to the European Commission (DG Sanco and DG RTD)
asking that EFSA
be provided with relevant data relating ongoing scientific experiments
and on statistics of
goats and sheep i.e. numbers tested for TSE/BSE and results in the
Member States taking
account of genotypes.
3. Letters were sent to EFSA’s Advisory Forum on 3rd of November 2004
and 30th of November
2004 in order to request that Member States and their national reference
laboratories and
different research institutes to provide EFSA with an update on any
planned or on-going
scientific research at national level linking BSE and small ruminants,
including studies on the
infectivity of milk.
4. A letter was sent to different leading European experts seeking their
contribution on an update
of scientific knowledge related to opinions available on the subject;
new findings arising from
the review of scientific literature, research projects ongoing, and
where available,
intermediate results or an indication of the timing of future results.
Outcome of all consultations: A summary of all contributions received
was discussed at the
first meeting (11
th
January 2005) of the working group on “Quantitative assessment of risk
posed to humans by tissues of small ruminants (SMRU) in case BSE is
present in these
animal populations”.
14
2. Assessing the safety of goat meat and goat meat products with
regards to TSE/BSE: state of play and future developments.
Following the first meeting of the working group (11
th
January 2005) constituted to address
the specific mandate with respect to the safety of goat meat and goat
meat products, the
expert group outlined its first conclusions concerning how best to
address the task at hand:
1. A full assessment of the feasibility of conducting a quantitative
assessment of the risks
involved in the consumption of goat products is, given the lack of new
published information
and the limitation of previous data, dependent to a great extent on the
availability of
unpublished findings from Member States and third countries. Key inputs
considered
indispensable for carrying out a quantitative risk assessment are data
related to:
a. The species barrier
b. Infectious load and distribution in goat tissues
c. Prevalence of infection
d. Human consumption levels.
If such data are not forthcoming or prove to be insufficient, there
would be no basis on which to
conduct a quantitative risk assessment (QRA) relative to the consumption
of goat meat and
goat meat products. Should this be the case, measures for the safe
sourcing of small
ruminant materials should be reviewed in respect to the level of BSE
infection in goats.
2. The epidemiological data available provided by the surveillance of
variant Creutzfeldt Jakob
Disease (vCJD) indicate that there is currently no evidence of a link
between goat meat
consumption and a higher risk of vCJD in certain ethnic groups (likely
to consume more goat
meat) of the UK population as compared with other groups. Similarly
there is also no
observed link on the occupational risk of handling goat meat and goat
meat products in the
UK. Such epidemiological analyses should also be made in other countries
where BSE has
been found. However, the BIOHAZ Panel recognises the lack of knowledge
with respect to
the incubation period of vCJD and exposure levels of the human
population which limits
confidence in these observations.
3. In addition to the quantitative risk assessment to be carried out by
EFSA, DG SANCO of the
European Commission introduced a three step testing scheme* in sheep and
goats (EC
regulation No 36/2005) and announced today an increased monitoring
programme in goats.
These measures will provide more data on the real prevalence of
suspected TSE cases (and
possible BSE infections) in goats. It is anticipated that the mid-term
evaluation of the results
of this increased surveillance (after 6 months) will concur with EFSA’s
opinion on the safety
of goat meat and goat meat products. EC regulation 999/2001further
specifies safety
measures already in place, such as the condemnation of the carcass of
cattle, sheep and
goats in case of a confirmed positive TSE case and the removal at
slaughter of Specified
Risk Materials (SRM) from cattle, sheep and goats.
*three step testing : rapid testing, discriminatory molecular testing
and mouse bio assay
testing.
15
SEAC 86/4
Annex 5
Summary of previous SEAC consideration of risks should BSE be found in
small ruminants
1. In April 2002 SEAC concluded:
• In line with previous SEAC advice, only animals carrying the
ARR allele should enter the food chain.
• On a precautionary basis, the 12-month cut off previously
advised by SEAC remained appropriate for ARR
heterozygotes. However, in view of existing SRM regulations
there was no justification for any age cut off in ARR
homozygotes.
• In line with SEAC advice in 2001, only milk from ARR
homozygote sheep can be considered as highly unlikely to
contain the infectious agent. Further experimental work was
required before potential risks from small ruminant milk from
goats and semi-resistant or susceptible sheep could be
excluded.
2. In June 2003 SEAC agreed there was no change in the risk
associated with consumption of milk from ARR homozygous sheep,
and endorsed its previous advice of April 2002.
3. In September 2004 data were presented to SEAC on the possible
maximum prevalence of BSE in the GB sheep flock. A statistical
analysis of these data, using an approach similar to that of Gravenor
et al. (2003)3, which assumed a skewed distribution in the data, had
provided two estimates of the possible proportion of the scrapie
cases that could be BSE: 0.14% based on the number of scrapie
cases and 0.66% based on the number of flocks. SEAC generally
3 Gravenor et al. (2003) Searching for BSE in sheep: interpreting the
results so
far. Vet. Rec. 152, 298-299.
16
accepted the approach used to model the possible prevalence of
BSE in sheep, but noted that:
• The model depended on the ability of the tests used to
effectively detect and discriminate between scrapie and BSE;
• Using the number of TSE affected flocks in the calculation of
prevalence was preferable to using individual TSE cases.
4. In November 2004 SEAC was informed of the finding of possible
BSE in a French goat. Although the data available at that time were
consistent with BSE, a definitive interpretation could not be provided
until further data from mouse bioassays were available. In January
2005 the TSE Community Reference Laboratory Expert Group on
Strains confirmed the presence of TSE infection in the French goat. http://www.seac.gov.uk/papers/paper86-4.pdf 1
SEAC 86/5
IMPLICATIONS OF THE FINDINGS OF HEIKENWALDER ET AL.
(2005)
ISSUE
1. FSA has asked SEAC to consider the implications of the findings
of a study by Heikenwalder et al. (2005)1.
BACKGROUND
2. Heikenwalder et al. (2005) report that in mouse models of
inflammatory disease, the tissue distribution of prions is altered
by chronic inflammation (Annex 1). In the study, five different
mouse models were generated by genetic modification to induce
chronic inflammation of the liver, kidney or pancreas (chronic
inflammation of both the liver and pancreas was induced in two
models). All the models expressed the murine prion protein
gene. Following parenteral challenge with the scrapie agent
(source unspecified) to each type of model, infectivity and
abnormal prions were detected in the liver, kidney and/or
pancreas in animals with chronic inflammation of these organs.
In contrast, no or borderline infectivity and no abnormal prions
were detected in these organs when wild-type mice were
challenged with the scrapie agent.
3. The authors suggest that tissue inflammation may modify the
tissue distribution of the infectious agent in prion diseases.
ADVICE SOUGHT FROM THE COMMITTEE
4. The committee is asked to comment on the implications of the
findings on the risk from the consumption of beef, or sheep and
goat meat, in the light of current specified risk material controls.
1 Heikenwalder M, Zeller N, Seeger H, Prinz M, Klohn PC, Schwarz P,
Ruddle NH,
Weissmann C, Aguzzi A. Chronic Lymphocytic Inflammation Specifies the
Organ Tropism of
Prions. Science. 2005 Jan 20; [Epub ahead of print]
SEAC 86/5
ANNEX 1
Heikenwalder et al. (2005) Chronic Lymphocytic Inflammation
Specifies the Organ Tropism of Prions. Science. http://www.seac.gov.uk/papers/paper86-5.pdf TSS
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