BSE
monthly report
February 2002
Featuring:
·
Science news
·
General news
·
Official figures
Science news
Bolt stunning contaminates both carcass and abattoir
Tests of captive bolt
stunning methods have revealed potential widespread contamination of the
environment and carcass with brain tissue.[1]
An experiment was
designed to test the degree to which current slaughter practices, using captive
bolt guns, may induce disruption of brain tissues and may mobilise central
nervous system (CNS) tissue into the bovine circulatory system, leading to the
dispersion of prion proteins throughout the derived carcass. A marker organism,
an antibiotic resistant strain of Pseudomonas fluorescens, was introduced by
injection through the bolt entry aperture, or directly using a cartridge-fired
captive bolt. The organism was detected in the slaughter environment
immediately after stunning and in the abattoir environment at each subsequent
stage of the slaughter-dressing process. The marker organism was also detected on
the hands of operatives; on slaughter equipment; and in samples of blood,
organs, and musculature of inoculated animals. There were no significant
differences between the results obtained by the two inoculation methods.
The authors suggest
that material present in, or introduced into, the CNS of cattle during
commercial captive bolt stunning may become widely dispersed across the many
animate and inanimate elements of the slaughter-dressing environment and within
derived carcasses including meat entering the human food chain.
No evidence for vCJD before 1996
Tests of brain tissue
in samples of patients who died prior to the first recorded case of vCJD have
failed to find any evidence of the disease being present before that date.[2]
Detection of earlier cases would suggest a shorter incubation period and might
lead to predictions of epidemic size being revised.
Examination of all
certified deaths (excluding external injury and poisoning) in residents of
Wales aged 15--45, between 1985 and 1995, were reviewed to detect vCJD deaths
that might have been overlooked. 12 091 deaths were reviewed, of which 3 322
were considered to be ‘Non-specific fatal disorders compatible with vCJD’.
Brain tissue was available for some 7% of cases and clinical information available
for those with neurological symptoms in 70% of cases. Sufficient clinical and
pathological information was available to exclude all these as potential cases
of vCJD, and the authors conclude that variant CJD is a new disease entity and
not simply the result of better case assessment.
Small primates show 3 month incubation periods
Small primates
infected with BSE showed signs of behavioural change within three months,
according to French researchers.[3]
Infection of eleven
Microcebus murinus (lemur) primates through intracerebral or oral routes, using
material infected by BSE or macaque-adapted BSE (MBSE) brain homogenates, led
to persistent behavioural changes as early as 3 months, and neurological signs
as early as 13 months, after infection, compared with animals given BSE-free
bovine brain preparations. Immunohistochemical examination of animals
sacrificed during the incubation period revealed an abnormal accumulation of
prion protein material in the intestinal wall, intestinal nervous plexus, mesenteric
lymph nodes and spleen, and in the clinical stage, also in the brain. Obvious
signs of neurodegeneration were observed in all infected animals characterised
by hyperaggregated and paired-helical filaments-immunoreactive Tau proteins,
beta 42-amyloid plaques and astrogliosis. Additionally, abnormal prions
(PrPres) were present in the ganglion cells of the retina in diseased animals
after either intracerebral or oral infection by the BSE or MBSE agent.
The authors suggest
that small primates are susceptible to the BSE infectious agent via
intracerebral and oral routes with comparatively short incubation periods
compared to simians, and that lemurs could be a useful animal model to study
disease transmission in primates.
Prions in skin and mucosa
Tests on mice show
the presence of normal prions in nervous tissue in the skin, as well as in the
mucosa and hair-forming cells.[4] The authors suggest that these cells may be
the initial sites of infection during peripheral inoculation, found with
scrapie in sheep.
Luminscence test proves reliable
A luminescence
immunoassay method for detecting BSE has been developed by researchers at
Prionics, the Swiss company pioneering BSE detection.[5] The technique uses two different monoclonal
antibodies for capture and detection of the protease-resistant fragment of the
pathological prion protein. Using more than 300 positive and 1400 negative
bovine or ovine samples, sensitivity and specificity of 100% were demonstrated.
One-thousand-fold dilutions of a BSE-positive homogenate still resulted in a
clear positive signal.
The authors conclude
that, in combination with a simple homogenisation procedure for the preparation
of the samples, the testing method lends itself for complete automation of
large scale screening of cattle and sheep.
Can TSE infection be controlled?
A review by Professor
Fraser of the Edinburgh-based Neuropathogenesis Unit suggests that there may be
pharmacological means of slowing the development of TSEs in their early stages,
possibly to the point where the disease incubation is prolonged beyond the
natural lifespan and the victim dies of other causes.[6]
Infection
has been compared to 'setting a clock' which then runs inexorably as the
disease spreads, usually through the lymphoreticular system and then via
peripheral nerves to the central nervous system (CNS), although the mechanism
controlling the protracted progression is not known. Recent research has
identified several means of slowing (if not stopping) the clock when infection
has not yet reached the CNS. Although the potential for later stage therapies
seems limited, neuroprotective strategies which have been shown to be effective
in other neurodegenerative conditions may also ameliorate TSE induced CNS
pathology.
Bovine heart for false eyes
In patients requiring
false eyes for permanent insertion, the standard procedure has been to use
sclera (eye-ball outer membrane, presumably from human cadaver sources) to hold
the false eye in place. Tests of the use
of bovine pericardium material, the membrane enclosing the heart, show that
this is a suitable alternative with a lower risk of transmission of BSE.[7] In a retrospective study on 27 patients,
followed up on average for 1.7 years, the cosmetic results and ocular movement
were satisfactory in all but one patient. The authors conclude that the ‘use of
bovine pericardium as wrapping material for the hydroxyapatite implants has
shown promising results with minimal extrusion rates, providing an effective
alternative for sclera, eliminating the potential risks of CJD’.
Antioxidants may slow CJD progress
The use of
antioxidant therapies may reduce the damage to CNS cells caused by
transmissible spongiform encephalopathies.[8]
In a case study of CJD in Kansas, the patient showed an early reversal in cognitive
decline and subsequent improvements in myoclonus, apnoea and rigidity following
antioxidant treatment. Although death was the ultimate outcome, the patient
succumbed to the illness 22 months after the onset of symptoms, whereas the
early rapid decline had led to a predicted demise within a few months.
The authors suggest
that strategies which block the effect of proinflammatory cytokines and the
resulting oxidative damage may stem the progressive damage to the nervous
system that occurs in spongiform encephalopathies. They call for further
investigation into the use of antioxidants and other types of agents quelling
inflammation, in combination with treatments for the primary infective agent.
Should all vCJD victims get quinacrine?
In response to the
suggestion that all patients diagnosed with vCJD should be prescribed the
anti-malarial drug quinacrine, following evidence that this slowed the progress
of the disease in a trial in California (see January BSE report), the British
Medical Journal has published a counter-argument stating that prescribing a
placebo, or allowing patients to self-select and opt out of quinacrine trials,
is legitimate.[9]
The authors argue
that quinacrine is not licensed in the UK, due to its side effects on damaging
the liver and skin, and these side effects are likely in patients taking
relatively high doses over a long period. They suggest that quinacrine is
unlikely to prevent eventual death, and that its effects on the progress of
vCJD may be fairly modest. Using past patients as controls is not feasible, as
there are too few detailed case histories on which to base a comparison.
Furthermore, quinacrine should not be prescribed until the diagnosis is clear
and all alternatives ruled out, which may be fairly far into the progress of
the disease.
Rapid detection of codon 129 homozygosity
Testing of patients
for their genetic vulnerability to vCJD can be conducted more rapidly using
polymerase chain reaction (PCR) techniques, according to German researchers.[10]
When analysed for
genetic patterns, 100% of cases of vCJD show methionine homozygosity (met/met)
at the codon 129 region of the prion gene, whereas this pattern is present in
the UK Caucasian population at around 43%. The implication is that met/met
homozygosity confers greater vulnerability to developing vCJD, either through a
lowered threshold for infection or through shorter incubation periods. Methods
of testing for met-met homozygosity are cumbersome and time-consuming, and
require extensive post-amplification manipulations which increase the risk of
contaminated results. To overcome these problems, the authors have developed a
method using PCR and temperature melting curve analysis. An initial test of
swabs and blood samples from 46 healthy donors showed the new technique to be
reliable and easy to perform. Results can be obtained within 2 hours, including
sample preparation.
US scientists claim detection of prion in urine
A US scientific
company has claimed it can detect prion proteins in as little as one millilitre
of urine.[11] According
to the company – Disease Sciences, Inc [www.diseasesciences.com] – previous
methods required up to 50ml urine and were less reliable. The company is now
working on differentiating normal from abnormal prion types.
European Commission advisors confirm current risk
assessments
The EC Scientific
Steering Committee has confirmed its current criteria for assessing the
Geographically-Based Risk for BSE, under which member states and third
countries are classified into categories (GBR I, no risk, to GBR IV, high risk)
according to the level of likelihood of BSE present in the region.[12]
The SSC has also commented on the current classifications for member states as
follows:
‘The information
provided by EU Member States when applying for BSE-status categorisation
clearly shows that since the last GBR assessment was finalised (July 2000) a
number of initiatives have been taken to ensure optimal stability and to reduce
the BSE-risk. However, it will require time until these measures will reduce
the GBR-level. BE, DE, DK, FR, IRE, IT, LUX, NL, SP remain in GBR III; PT and
UK will remain in GBR IV. For AT, SF, SW and GR a detailed up-to-date GBR
assessment will be provided in separate scientific opinions of the SSC.’ (NB AT=Austria, SF=Finland).
SSC recommends caution on using pig intestine extracts in
feed
A commercial supplier
of protein peptides derived from pig intestine mucosa asked the SSC to comment
on the likelihood that the peptides presented a risk of TSE contamination in
animal feed.[13] In response the SSC stated that it was
unlikely that such peptides presented a risk provided that the risk of contamination with a TSE agent from
TSE-susceptible
species from external sources can be excluded. ‘Such sources are for
example: contaminated animal feed
given in the days prior to slaughter, cross-contamination with ruminant SRMs
during slaughter, slaughter on non-dedicated lines in
non-GBR I countries used also for
slaughtering ruminants, or the inclusion of possibly
TSE-infected animal material in the
medium used for the growth of the micro-organisms
from which the serine endopeptidase
may have been isolated.’
SSC specifies field trial procedures for rapid BSE testing
techniques
The SSC has drawn up
a protocol for the testing of candidate techniques for rapid testing of BSE.[14]
To ensure high levels of sensitivity (detecting true positives) 200 positive
samples should be tested, to be confident that a test has a sensitivity not
below 98.5% compared with current testing procedures. To ensure high levels of
specificity (not creating false positives) 10 000 consecutive samples from
healthy slaughtered animals should be tested, to be confident that the test has
a specificity between 99.95% and 99.99% compared with current methods. Other
criteria are given in the SSC report.
General news
EU Parliament criticises BSE progress
A plenary session of
the EU Parliament on 6 February adopted the Olssen report on the handling of
the BSE crisis by the Commission and by Member States. The report criticises
member states for their slow and inadequate response to enforcing the BSE
legislation, noting that farmers in some member states were still feeding meat
and bone meal to their animals.[15]
Commissioner David Byrne, responding to the Parliamentary debate, welcomed the
report and listed the measures now in place to restrict the spread of BSE.[16]
He agreed that there was room for improvement in surveillance efforts, as also
identified by the Commission’s own Food and Veterinary Office reports, and
there were continuing problems with member states dealing with the destruction
of huge quantities of meat and bone meal. He also expressed concern about the
potential presence of BSE in sheep, and has introduced higher testing levels to
improve surveillance for the disease.
The Olssen report
called for all for bovines entering the food chain aged over 24 months to be
tested for BSE, instead of the current 30-month requirement, but the Commission
has resisted this, except in the case of casualty cattle or animals at risk.
EC sets testing criteria for sheep
An extension of the
criteria for testing sheep and goats for TSEs has been adopted by the European
Commission, stepping up the numbers which must be tested, raising the total for
the EU from 164 000 to 560 000 per year..[17]
The new regulations
will come into effect on 1 April 2002, and will include a large number of
healthy animals and a further number of animals that die on the farm aged over
18 months. The Commission is raising its budget for the costs of purchasing
testing kits from €2.9m to over €6.9m.
Tests
to be required on healthy and dead-on-farm animals per Member State:
|
Member State |
Healthy
animals Minimum
Annual Sample Size |
Dead-on-farm
animals Minimum
Annual Sample Size |
|
Austria |
8 200 |
1 100 |
|
Belgium |
3 750 |
450 |
|
Denmark |
3 000 |
400 |
|
Finland |
1 900 |
250 |
|
France |
60 000 |
6 000 |
|
Germany |
60 000 |
6 000 |
|
Greece |
60 000 |
6 000 |
|
Ireland |
60 000 |
6 000 |
|
Italy |
60 000 |
6 000 |
|
Luxembourg |
250 |
30 |
|
Netherlands |
39 000 |
5 000 |
|
Portugal |
22 500 |
6 000 |
|
Spain |
60 000 |
6 000 |
|
Sweden |
5 250 |
800 |
|
United Kingdom |
60 000 |
6 000 |
Meanwhile France has
announced its intention to test 100 000 sheep (60 000 older animals entering
the food chain and 40 000 casualty animals excluded from the food chain).[18]
It will use BioRad and Prionics test kits.
Commissioner Byrne hints at calf tallow ban
EC Commissioner David
Byrne has suggested to a meeting of Agriculture Ministers that the EC may
introduce a ban on the use of tallow in calf milk replacers.[19] A regulation is already proceeding through
the Commission and Parliament on the use of animal by products, but controls
over calf replacers may require further legislative measures.
Several German states recall beef
Food control
authorities in four of Germany’s länder
have ordered the recall of beef following evidence of irregularities in BSE
testing laboratories.[20]
A laboratory in Bavaria was closed in January after it was found to be testing
animals without a license. Several other laboratories in three other states
have now had their licenses suspended following evidence of poor or incorrect
testing procedures.
BSE offspring enter UK food chain
Two further cases of
animals entering the food chain despite being the offspring of known BSE cases
were admitted by the government in February.[21] The Food Standards Agency said it was
concerned about the continuing breaches of controls, although there was little
likelihood that the two animals involved had BSE.
One animal, aged 15
months, was slaughtered in December 2001 and sold into the food chain. None of
the meat is now left. The second, aged 26 months, was slaughtered in January
and some of the meat has entered the food chain. The remainder has been
destroyed.
The animals were sold
for slaughter despite the farmers having been served with restriction notices.
Government Minister Elliot Morley has said that cattle passports which permit
the movement of animals should not be returned to farmers after restrictions
have been ordered, as happened in these cases. These are the second and third
times this year that BSE meat controls have failed.[22]
French schools return to beef
Beef is returning to
the school menu in France according to a recent survey.[23]
The French Meat Information Centre reports that only 3% of administrative
communes are maintaining a ban on beef in school canteens, compared with 67% in
the early stages of the BSE crisis. Traceability schemes have helped restore
confidence, but meat products and minced beef are still off the menu in many
areas.
BSE in animal born 1999 in Northern Ireland
Northern Irish hopes
of winning an exemption from the UK-wide ban on beef exports were set back when
a case of BSE in an animal born in 1999 (aged just 31 months) was confirmed in
early February.[24] The Belfast
department of agriculture suggested that maternal transmission appeared the
most likely cause. The animal’s mother was born in 1996. This is the second
‘born after the mammalian ban’ case in Northern Ireland in recent months, and
local farmers’ hopes of having the province declared a lower-risk region than
the rest of the UK looks weaker now than it did at the end of 2001.
BSE not transmitted by embryos or semen
Eggs and semen from
BSE-infected cattle, implanted into healthy dams, does not lead to BSE in
either the calves or the surrogate mothers, according to government adviser
Professor John Wilesmith of the Veterinary Laboratories Agency.[25]
The Meat and Livestock Commission immediately called for a lifting of the ban
on the export of cattle embryos. There were also calls for the suspension of
further culls of BSE offspring (the BSE Offspring Cull has destroyed over 20
000 offspring of BSE cattle since 1998).
Uterine fluids and
secretions were also tested by inoculation into mice, of which one developed
BSE but in such a short period (47 days) that the result was discounted as
anomalous. Wilesmith was cited as saying that he thought contamination might be
coming into the UK from imports of cattle feed contaminated with meat and bone
meal during shipping. Commentators have questioned whether the report, which is
due to be published in the Veterinary
Record, fully rules out the role of placental blood supplies, or
contamination with blood during birth, as routes of transmission.
New TSE controls introduced
Consolidation of the
UK’s anti-BSE control measures to comply with EU-wide regulations (principally
EC Regulation 999/2001) will lead to several new regulations being adopted in
the UK.[26]
New regulations include:
* A requirement that
the collection and transport of SRM is in separate vehicles from non-SRM
vehicles;
* Live animals must
be kept separate from animal products in premises that are permitted to use SRM
for production and live animals for research;
* Vertebral column
from cattle over 30 months old must be treated as SRM and removed in licensed
cutting plants (in the UK this will largely affect cattle under the Beef
Assurance Scheme which may enter the food chain up to age 42 months).
Consultation is open
until 11 March 2002, and the regulations are expected to be introduced in April
2002.
Cattle ash re-burial follows water pollution fears
Animals burnt and
buried under the Foot and Mouth control measures are to be exhumed and reburied
following fears that their ashes are contaminating water supplies.[27]
Ash from 160 sites was being removed at a cost of Ł30m, to be re-buried in
landfill sites in Buckinghamshire and West Cumbria.
A letter from DEFRA
to one landowner is reported to have stated that DEFRA had asked the
Environment Agency for an assessment ‘on the chance that cattle with BSE could
have been buried on the site’ and the Agency had recommended it would be better
to remove the ash. However, a DEFRA spokesperson is also reported to have said
that ‘It has nothing to do with BSE, but with other trace elements in the ash’.
Japan blames Italy for BSE cases
The Japanese
government has suggested that imports of MBM from Italy before 1998 may have
been responsible for its recent cases of BSE.[28]
The agriculture ministry, which sent experts to all countries from which it had
imported MBM, says that a company in Italy was using equipment which could not
have produced the necessary sterilising pressure required under EU law.
EU regulations
introduced in April 1997 specify that MBM must be sterilised at a temperature
of 133 degrees, for 20 minutes, at a pressure of three bars. Italy exported
some 606 tonnes of MBM to Japan between 1995 and June 1998.
Snow Brand closes after beef scandal
The Japanese meat
company, Snow Brand Foods, is to close after it was caught in a mislabelling
scandal that has raised consumer worries about mad cow disease.[29]
Nearly 1000 workers will be lose their jobs.
The directors of Snow
Brand Foods, Japan's sixth-biggest meat packer, decided to liquidate the
company following revelations that the company deliberately passed off Australian
beef as Japanese in an attempt to gain access to government grants for
disposing of older beef products. The company's president apologised for the
events that led to the decision to shut the 52-year-old meat company. ‘I feel
as if my heart has been broken when I think of the workers and their families
who had nothing to do with the scandal,’ said company president Koshiro Iwase.
‘We are painfully aware of our responsibility for losing the public's trust in
meat labelling.’
A Japanese government
spokesman described the development as rough justice. ‘It was the penalty that
the company had to pay for betraying consumers' confidence,’ Chief Cabinet
Secretary Yasuo Fukuda said. Japanese supermarkets removed Snow Brand beef from
their shelves, and schools stopped using it in school meals. The scandal was
another blow to the reputation of the meat packer's parent, a dairy products
conglomerate that was blamed for producing tainted milk that caused the
country's largest case of food poisoning in July 2000. The Japanese police are
reportedly building a fraud case against the company.
Meanwhile beef sales
in Japan are reported to have fallen to virtually half the levels sold prior to
the first BSE case last September.[30]
Sales during November 2001 averaged 421 grams per household, compared with 827
grams in the same period in 2000.
Colorado prepares for mass deer slaughter
Hunters and state
biologists are preparing to kill 4 500 deer in three northern Colorado herds
under a plan approved by wildlife officials to contain chronic wasting disease.[31]
The plan slaughter would be spread over two to five years
Some mountain
homeowners and animal-welfare activists had criticised the plan as too
excessive and asked for more research on chronic wasting disease. They feared
that mountain lions, with fewer deer to stalk, would turn to pets and
livestock. Others suggested that chronic wasting disease may be a natural check
on population. Some opponents said officials should kill only sick deer that
are identified through a tonsil test, but this was deemed by authorities as too
difficult to implement.
Italy acknowledges two possible vCJD cases
Italian medical
authorities have acknowledged that two suspected cases of vCJD have been
reported in a hospital in Palermo, Sicily.[32]
The first case, a 23-year-old woman, has been under observation since June
2001, and her diagnosis was announced following tests in Italy and the UK.
Results of tests for the second case, a 56-year-old man, are still awaited.
Government names vCJD trust members
Alan Milburn,
Secretary of State for Health, has appointed seven trustees to the vCJD Trust
to administer the scheme for compensating those who have been diagnosed with
vCJD and their families.
The Trustees are:
Sir Robert Owen QC
(Chairman), a High Court judge;
David Churchill,
member of the Human BSE Foundation and carer of a vCJD victim;
Malcolm Tibbert,
member of the Human BSE Foundation and carer of a vCJD victim;
John Melville
Williams, QC, first president of the Association of Personal Injury Lawyers;
Elaine Motion,
personal injury lawyer and expert on Scottish law;
David Stevens,
consultant neurologist;
Vicki Vidler,
specialist nurse for patients with complex needs.
The scheme is limited
to compensation for the first 250 victims, after which it will be reviewed and
an updated scheme may then be put in place.
Government considering importing frozen plasma
The Department of
Health is considering importing supplies of blood plasma for use in surgical
operations for babies and young children, as a precautionary measure to reduce
the risk of using vCJD-contaminated blood from UK donors.[33]
Very young patients are considered most at risk because they have the longest
period to incubate the disease. Some 70 000 operations may be affected.
Hong Kong vCJD victim dies
The first Asian
victim of vCJD, a 35-year-old Hong Kong woman, has died.[34]
The woman, who has not been named, is believed to have contracted the disease
between 1985 and 1992 when she lived in Britain, where she owned a restaurant with
her husband. She returned to Britain regularly after moving back to Hong Kong
in the mid-1990s and first went to hospital for treatment early last year.
Dentists refuse treatment to vCJD families
The family of a vCJD
victim have been refused treatment by their local dentist and referred to a
dental hospital, on the grounds that there are insufficient equipment
sterilising facilities in the local surgery.[35]
Confusion has arisen
because Health Department guidelines insists on hospital dental treatment for
confirmed cases, suspected cases and those deemed ‘at risk’ but these do not
specify the families of vCJD patients. A Department spokesman said: 'The
guidance does not currently differentiate between types of CJD in this context…
The guidance is vague and is currently under review. Families with a case of
new variant CJD do not pose a risk.'
Drug companies resisting BSE enquiries
Details on the
production specifications of a third of UK medicines have not been supplied by
pharmaceutical companies, two months after the closing date requested by the
Department of Health.[36]
The Medicines Control Agency is reported to have said that by the beginning of
February companies had sent details about the manufacturing processes and
ingredients for only 12,000 of 17,500 licensed products, despite a deadline of
1 December 2001.
Comprehensive
European legislation was drawn up in 1999, and drug companies legally have
until 1 March to comply. But the government set a December deadline in order to
ensure the rules were being obeyed before the EU law took effect. Under the new
measures, the European Commission requires information about all medicines,
including those that did not include animal products in their manufacture.
Last autumn, the
government had to withdraw an oral polio vaccine developed using material from
British cows. Guidelines have been in place since 1989 to ban use of bovine
sources from BSE-infected countries in injected vaccines, and oral medicines
were meant to follow suit. Frances Hall, of the Human BSE Foundation, said:
‘The companies do seem to be dragging their feet. It has not been proved that
some cases (of vCJD) came from injections. I still have my suspicions that some
of them did. People have been tardy getting on top of this.’
Safety officials are
also reviewing the manufacture of vaccines made during the 1970s, following the
Phillips inquiry suggestion that BSE may have been growing unnoticed up to 15
years before it was recognised in 1986.
Official figures
BSE
Within the EU, only Sweden
remains officially BSE-free. Figures collected by the Office International Des
Epizooties of the World Health Organization[37]
updated with figures from national authorities and news sources[38]
show the following incidence of BSE.
Reported cases of BSE
includes those
detected during testing programmes
latest available
figures, 1 March 2002
|
country |
total 2001 |
2002 to 1 March |
total since
1987 |
|
Great Britain |
1 118 |
97 |
178 849 |
|
Northern Ireland |
50 |
0 |
1 913 |
|
Isle of Man |
0 |
0 |
438 |
|
Guernsey |
1 |
0 |
696 |
|
Alderney |
0 |
-- |
2 |
|
Jersey |
0 |
0 |
152 |
|
Total UK |
1 169 |
97 |
182 050 |
|
Azores |
0 |
-- |
1 |
|
Austria |
1 |
0 |
1 |
|
Belgium |
46 |
8 |
72 |
|
Canada |
0 |
0 |
1 |
|
Czech Republic |
2 |
0 |
2 |
|
Denmark |
6 |
0 |
8 |
|
Falkland Islands |
0 |
0 |
1 |
|
Finland |
1 |
0 |
1 |
|
France |
274 |
52 |
568 |
|
Germany |
125 |
27 |
163 |
|
Greece |
1 |
0 |
1 |
|
Ireland |
246 |
72 |
916 |
|
Italy |
50 |
7 |
59 |
|
Japan |
3 |
0 |
3 |
|
Liechtenstein |
0 |
0 |
2 |
|
Luxembourg |
0 |
0 |
1 |
|
Netherlands |
20 |
4 |
32 |
|
Oman |
0 |
0 |
2 |
|
Portugal |
101 |
0 |
612 |
|
Slovakia |
5 |
0 |
5 |
|
Slovenia |
1 |
1 |
2 |
|
Spain |
82 |
14 |
98 |
|
Switzerland |
42 |
4 |
408 |
|
Ukraine |
1 not confirmed |
0 |
1 not confirmed |
|
Total non-UK |
1 006 |
185 |
2 951 |
BSE tests
The results of the
testing of healthy adult cattle entering the food chain or for surveillance
purposes, required under EU regulations, are shown below. The table also shows
tests of fallen cattle or those presenting as ill at the abattoir. The results
of testing have been widely interpreted as signifying that there is no large
epidemic of undetected BSE in Europe.[39]
BSE test results[40]
latest available
figures: healthy cattle to 31/12/2002, cattle at risk to 30/11/2001
|
Country |
Adult cattle
(million) |
Tests on
healthy cattle * |
Positive
cases |
Tests on
cattle at-risk** |
Positive
cases |
|
Austria |
1.0 |
216 045 |
1 |
8 462 |
0 |
|
Belgium |
1.5 |
359 435 |
28 |
14 559 |
15 |
|
Czech Republic |
|
>40 000 |
2 |
|
|
|
Denmark |
0.9 |
250 412 |
3 |
24 430 |
3 (208 pending) |
|
Finland |
0.4 |
9 882 |
0 |
16 296 |
1 |
|
France |
11.0 |
2 382 225 |
83 |
122 663 |
176 |
|
Germany |
6.6 |
2 565 341 |
36 (4 pending) |
271 115 |
85 (3 pending) |
|
Great Britain*** |
5.3 |
41 510 |
64 |
86 216 |
386 |
|
Greece |
0.3 |
15 360 |
1 |
1 595 |
0 |
|
Ireland |
3.4 |
636 930 |
34 |
31 765 |
194 |
|
Italy |
3.4 |
377 201 |
27 |
60 705 |
19 |
|
Japan |
|
10 000 |
3 |
|
|
|
Lithuania |
|
>19 254 |
0 |
|
|
|
Luxembourg |
0.1 |
19 475 |
0 |
1 345 |
0 |
|
Netherlands |
1.8 |
454 649 |
11 |
41 694 |
9 (315 pending) |
|
Norway |
|
5 225 |
0 |
|
|
|
Poland |
|
11 759 |
0 |
|
|
|
Portugal |
0.8 |
28 384 |
17 (2 pending) |
9 300 |
73 (35 pending) |
|
Spain |
3.4 |
328 517 |
35 (14 pending) |
49 687 |
44 (18 pending) |
|
Sweden |
0.7 |
4 433 |
0 |
22 122 |
0 |
|
Switzerland |
|
149 292 |
13 |
|
|
* Healthy animals
subject to normal slaughter.
** Animals suspected
of having BSE, animals from herds with BSE, animals born, reared or fed in
cohorts with BSE cases, offspring of BSE cases, dead-on-farm animals, emergency
slaughtered animals, animals sent for normal slaughter but found sick at the
ante-mortem inspection.
*** Results include
those reported under the UK active surveillance (DEFRA Weekly BSE statistics).
BSE in Britain
A continuing decline
in the observed cases of BSE is reported in official tables, as shown below.
GB: Confirmed BSE cases[41]
Annual cases*
No of cases reported
22/02/02, herds to October, reported 1/1/02
|
|
Cases |
new herds |
|
to end 1987 |
442 |
324 |
|
1988 |
2 184 |
1 875 |
|
1989 |
7 137 |
3 357 |
|
1990 |
14 181 |
4 428 |
|
1991 |
25 032 |
5 767 |
|
1992 |
36 682 |
7 204 |
|
1993 |
34 370 |
5 746 |
|
1994 |
23 945 |
2 626 |
|
1995 |
14 302 |
1 382 |
|
1996 |
8 016 |
751 |
|
1997 |
4 312 |
480 |
|
1998 |
3 179 |
399 |
|
1999 |
passive reports: 2256 active testing: 18 |
248 |
|
2000 |
passive reports: 1 311 active testing: 44 |
169 |
|
2001 |
passive reports: 746 active testing: 317 |
93 |
|
2002 to date |
passive reports: 43 active testing: 57 |
not available |
* The dates refer to
the year when the animal was first suspected of harbouring the disease, and the
figures are for animals finally confirmed as having the disease. Recent figures are still provisional.
Predictions for cases
of BSE made by the Veterinary Laboratory Agency in July are:
Predicted BSE cases[42]
|
|
Estimate of confirmed cases |
95% lower boundary |
95% upper boundary |
|
2001 |
504 |
353 |
655 |
|
2002 |
183 |
93 |
273 |
|
2003 |
57 |
7 |
107 |
Current statistics show:
·
Incidence among
cattle over 24 months old: 219 cases per million[43]
(United Kingdom, January 2001 – December 2001)
·
Proportion of cattle
herds affected: 37.7%[44]
·
Proportion of dairy
herds affected: 61.5%[45]
·
Proportion of beef
suckler herds affected: 16.8%[46]
By mid-November, the
United Kingdom had seen over 182 000 cases of BSE affecting over 35 000 farms.
The incidence of BSE is falling, but against this decline in the number of
cases must be set the possibility that cattle carrying BSE have been
slaughtered before showing the disease, under the following schemes:
* the Selective
Culling scheme which, since it began in early 1997, has removed over 77 300 UK
cattle at greatest risk of developing BSE based on their herd and feeding
histories,[47]
* the Over Thirty
Month slaughter scheme which, since April 1996 has removed over 5.4 million
older cattle from the national herd, a rate of about 8% of cattle each year (19%
of adult animals),[48]
in addition to an unspecified number of older cattle culled under the foot and
mouth disease culling regime.
* the BSE Offspring
Cull, which since October 1998 has found over 22 900 offspring of BSE cases
that have been, or will be, slaughtered.[49] Nearly four hundred animals are awaiting
slaughter under this scheme, and 176 are deemed untraceable.
Around 84% of UK BSE
cases now being reported are in animals born after the original ruminant
protein ban of 1988, which had been introduced to prevent the further spread of
the disease. Its clear failure led to tougher regulations applied in mid-1996,
when all mammalian meat and bone meal was banned from ruminant feeds (subject
to some loopholes), but since then several animals born after the mid-1996 ban
have been diagnosed with BSE. Latest DEFRA figures (15 January 2002) for Great
Britain are shown below, but a subsequent news report suggests that ten
animals are known to have been born in Britain after the 1996 ban, plus three
in Northern Ireland.[50]
BSE in cattle born after the start of 1996, Great Britain[51]
(DEFRA 15 January
2002)
|
date of birth |
cases
awaiting diagnosis |
Cases
confirmed |
|
Jan-July 1996 |
3 |
12 |
|
Aug-Dec 1996 |
0 |
4 |
|
1997 |
3 |
3 |
|
1998 |
4 |
0 |
|
1999 |
1 |
0 |
|
2000 |
1 |
0 |
|
Total after 1/8/96 |
9 |
7 |
According
to DEFRA, expert advisers predicted in July 2001 that the number of cases born
after 1 August 1996 would be as follows:[52]
|
Year |
Predicted cases
in animals born after mid 1996 |
95% confidence
intervals |
|
|
|
|
Lower |
Upper |
|
1999 |
2 |
0 |
5 |
|
2000 |
6 |
3 |
16 |
|
2001 |
9 |
9 |
23 |
The
figures assume that 10% maternal transmission occurs where calves are born to
infected dams within 6 months of clinical onset.
Whether the cases
that have occurred have been the result of insufficient enforcement of the feed
ban, or because maternal transmission has perpetuated the disease or because
there are other agents which are not yet controlled, has not been determined.
In the case of one animal, the mother survives and is not affected by BSE.[53]
There is a fear that
farmers may be reluctant to declare BSE in their herds, given that there is a
market among organic and organic-conversion farmers for cattle from BSE-free
herds[54]
(farmers converting to organic status must buy cattle that have not been the
progeny or cohort of a BSE case, and fully organic farmers must buy cattle only
from farms free of BSE since the end of 1993). Compensation for farmers with
BSE is currently Ł560 for confirmed cases and around Ł700 for cases which are
found to be BSE-free at post-mortem.
Scrapie
Data on scrapie in
sheep and goats have been collected since the disease became notifiable 1993.[55] Not all cases were confirmed until
compulsory slaughter legislation was introduced in 1998. Interpretation of trends may therefore be
unreliable.
Scrapie cases (Great Britain)
(DEFRA, 31 December
2001)
|
|
confirmed |
pending or inconclusive |
|
1993 |
328 |
0 |
|
1994 |
235 |
0 |
|
1995 |
254 |
0 |
|
1996 |
460 |
0 |
|
1997 |
508 |
0 |
|
1998 |
499 |
0 |
|
1999 |
597 |
0 |
|
2000 |
568 |
0 |
|
2001 to 31 December |
248 |
64 |
FSE
Feline Spongiform
Encephalopathy has been reported in since 1990. One case has been reported in Northern Ireland and others in
Norway, Liechtenstein, Switzerland and Italy. The figures for Great Britain are
as follows:
FSE cases (Great Britain)[56]
(MAFF, updated 31
December 2001)
|
|
FSE cases |
of which born after SBO ban in
petfood |
|
1990 |
12 |
0 |
|
1991 |
12 |
0 |
|
1992 |
10 |
0 |
|
1993 |
11 |
0 |
|
1994 |
16 |
0 |
|
1995 |
8 |
0 |
|
1996 |
6 |
1 |
|
1997 |
6 |
2 |
|
1998 |
4 |
2 |
|
1999 |
2 |
1 |
|
2000 |
1 |
1 |
TSEs in zoo
animals
Transmissible
Spongiform Encephalopathies in zoo animals have been noted since 1990. The
following species have been affected in zoos in Great Britain:
TSE in zoo animals[57]
(MAFF, updated 31
December 2001)
|
species |
number of cases |
|
Ankole cow |
2 |
|
Bison |
1 |
|
Cheetah |
5 |
|
Eland |
6 |
|
Gemsbok |
1 |
|
Kudu |
6 |
|
Lion |
4 |
|
Nyala |
1 |
|
Ocelot |
3 |
|
Arabian oryx |
1 |
|
Scimitar oryx |
1 |
|
Puma |
3 |
|
Tiger |
3 |
CJD
CJD cases
One hundred and
sixteen cases of vCJD had been reported in the UK up until 4th March
2002. There have also been four (possibly five[58])
cases in France (one of which was probably due to the ingestion of bovine pituitary
extract as a sports dietary supplement), one case in Hong Kong in an ex-UK
resident,[59] one case in
Ireland,[60]
and possibly two cases in Italy[61]
(see News section).
Suspected CJD (referrals)[62]
|
|
CJD
referrals |
|
1990 |
53 |
|
1991 |
75 |
|
1992 |
96 |
|
1993 |
78 |
|
1994 |
116 |
|
1995 |
87 |
|
1996 |
134 |
|
1997 |
161 |
|
1998 |
154 |
|
1999 |
169 |
|
2000 |
178 |
|
2001 |
172 |
|
2002 to
4 March |
23 |
Suspected vCJD cases alive: 7
CJD deaths[63]
|
|
Probable and confirmed
vCJD |
Sporadic CJD |
Other CJDs |
|
1985 |
-- |
26 |
2 |
|
1986 |
-- |
26 |
0 |
|
1987 |
-- |
23 |
1 |
|
1988 |
-- |
22 |
2 |
|
1989 |
-- |
28 |
4 |
|
1990 |
-- |
28 |
5 |
|
1991 |
-- |
32 |
4 |
|
1992 |
-- |
44 |
8 |
|
1993 |
-- |
38 |
8 |
|
1994 |
-- |
51 |
8 |
|
1995 |
3 |
35 |
9 |
|
1996 |
10 |
40 |
10 |
|
1997 |
10 |
59 |
11 |
|
1998 |
18 |
63 |
8 |
|
1999 |
15 |
61 |
8 |
|
2000 |
28 |
48 |
4 |
|
2001 |
20 |
48 |
7 |
|
2002 to 4 March |
5 |
3 |
1 |
|
Total |
109 |
549 |
92 |
Abbreviations
BSE = Bovine
Spongiform Encephalopathy, a disease of cattle first recognised circa 1986.
CJD = Creutzfeldt
Jakob Disease, a human form of spongiform encephalopathy.
CWD = Chronic Wasting
Disease, a TSE found in elk and deer in mid-west USA.
DEFRA = UK Department
for the Environment, Food and Rural Affairs (absorbed MAFF).
DoH = UK Department
of Health.
EC = European
Commission, the executive arm of European governance.
FSA = UK Food
Standards Agency.
MAFF = UK Ministry of
Agriculture, Fisheries and Food (replaced by DEFRA in 2001).
MBM = Meat and
bonemeal, made from rendered carcasses and used in high-protein animal
feed. Mammalian MBM is not permitted to
be fed to ruminant mammals.
MRM = Mechanically
Recovered Meat, scraped from bones and connective tissue.
OTM = Over Thirty
Month scheme in the UK prohibiting older cattle from the food chain.
SBO = Specified
Bovine Offal, cattle offal prohibited from human food supplies.
SEAC = the Spongiform
Encephalopathy Advisory Committee, a UK-government-appointed expert advisory
group.
SRM = Specified Risk
Material, ruminant offal prohibited from human food supplies.
SSC = the Scientific
Steering Committee, an EC-appointed expert advisory group.
TSE = Transmissible
Spongiform Encephalopathy, a general term for the family of diseases including
BSE, scrapie in sheep and vCJD in humans.
vCJD = the new form
of Creutzfeldt Jakob Disease which has been linked to BSE in cattle. (The ‘v’
stands for ‘variant’ or ‘new variant’.)
References