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 £30m, 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 £560 for confirmed cases and around £700 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



[1] Daly DJ, Prendergast DM, Sheridan JJ, Blair IS, McDowell DA. Use of a Marker Organism To Model the Spread of Central Nervous System Tissue in Cattle and the Abattoir Environment during Commercial Stunning and Carcass Dressing. Appl Environ Microbiol 2002 Feb;68(2):791-8

[2] Hillier CE, Salmon RL, Neal JW, Hilton DA. Possible underascertainment of variant Creutzfeldt-Jakob disease: a systematic study. J Neurol Neurosurg Psychiatry 2002 Mar;72(3):304-309.

[3] BSE infection of the small short-lived primate Microcebus murinus. Bons N, Lehmann S, Nishida N, Mestre-Frances N, Dormont D, Belli P, Delacourte A, Grassi J, Brown P. C R Acad Sci III 2002 Jan;325(1):67-74.

[4] Sugaya M, Nakamura K, Watanabe T, Asahina A, Yasaka N, Koyama Y, Kusubata M, Ushiki Y, Kimura K, Morooka A, Irie S, Yokoyama T, Inoue K, Itohara S, Tamaki K. Expression of cellular prion-related protein by murine Langerhans cells and keratinocytes. J Dermatol Sci 2002 Feb;28(2):126-34.

[5] Biffiger K, Zwald D, Kaufmann L, Briner A, Nayki I, Purro M, Bottcher S, Struckmeyer T, Schaller O, Meyer R, Fatzer R, Zurbriggen A, Stack M, Moser M, Oesch B, Kubler E. Validation of a luminescence immunoassay for the detection of PrP(Sc) in brain homogenate. J Virol Methods 2002 Mar;101(1-2):79-84.

[6] Fraser JR. What is the basis of transmissible spongiform encephalopathy induced neurodegeneration and can it be repaired? Neuropathol Appl Neurobiol 2002 Feb;28(1):1-11.

[7] Gupta M, Puri P, Rennie IG. Use of bovine pericardium as a wrapping material for hydroxyapatite orbital implants. Br J Ophthalmol 2002 Mar;86(3):288-9.

[8] Drisko JA. The use of antioxidants in transmissible spongiform encephalopathies: a case report. J Am Coll Nutr 2002 Feb;21(1):22-5.

[9] Angus M Kennedy, Sarah Walker, Daffyd Thomas, Martin Rossor, Janet Darbyshire, John Collinge. Quinacrine in possible or probable CJD. British Medical Journal, electronic responses, 27 February 2002.

[10] Schalasta G, Roth B, Enders G. Rapid typing of the codon 129 polymorphism of the human prion protein gene by combined real-time PCR and melting curve analysis. Clin Lab 2002;48(1-2):25-30.

[11] Business Wire, 19 February 2002.

[12] Opinion Of The Scientific Steering Committee On The Geographical BSE-Risk (GBR) And Its Evolution Over Time In The European Union Member States, Adopted by the SSC at its plenary meeting of 21-22 February 2002. This opinion was prepared by the GBR-Peer Group and endorsed by the TSE/BSE ad-hoc group at its meeting on 7/2/2002, Brussels 21-22 February 2002.

[13] Opinion On Peptides From Pig Mucosa: Risks With Respect To TSEs Adopted By The Scientific Steering Committee At Its Meeting Of 21-22 February 2002, Brussels, 21-22 February 2002.

[14] Opinion Of The SSC On Design Of A Field Trial For The Evaluation Of New Rapid BSE Post Mortem Tests, Adopted On 22 February 2002, Brussels, 22 February 2002.

[15] AgraNet, 1 March 2002.

[16] D Byrne, Speaking Note on the Olssen Report, Strasbourg, 5 February 2002.

[17] Extension of TSE tests in sheep and goats, press release ip/02/255, Brussels, 14 February 2002

[18] AgraNet, 1 March 2002.

[19] SPEECH/02/73 David Byrne, European Commissioner for Health and Consumer Protection, Latest developments in relation to BSE, Agriculture Council, Brussels, 18 February 2002.

[20] AgraNet, 8 February 2002.

[21] AgraNet, 15 February 2002.

[22] FSA, 14 February 2002; J Mason, Financial Times, 15 February 2002.

[23] AgraNet, 8 February 2002.

[24] AgraNet, 8 February 2002.

[25] R Uhlig, Daily Telegraph, 26 February 2002; AgraNet, 1 March 2002.

[26] Circular draft proposals on The Transmissible Spongiform Encephalopathy (England) Regulations 2002, DEFRA, 8 February 2002.

[27] P Hetherington, The Guardian, 9 February 2002.

[28] AgraNet, 15 February 2002.

[29] Ozo Mizoguchi, Associated Press, 22 February 2002.

[30] The Daily Yomiuri, 11 February 2002.

[31] Associated Press, 22 February 2002.

[32] Agence France Presse, 8 February 2002.

[33] J Meikle, The Guardian, 23 February 2002.

[34] Deutsche Presse-Agentur, 22 February 2002.

[35] S Mcintyre, Daily Mail, 21 February 2002.

[36] J Meikle, The Guardian, 20 February 2002.

[37] Office International des Epizooties [www.oie.int]

[38] See for example, Jan Braakman’s web page [http://ourworld.cs.com/_ht_a/j1braakman/BSE.htm].

[39] Food Standards Agency, Press Releases, 13 and 29 June 2001.

[40] European Commission [http://europa.eu.iint/comm/food/fs/bse/testing/bse_results_en.htm] and FSA [http://bsereview.org.uk] and Braakman [http://ourworld.cs.com/_ht_a/j1braakman/BSE.htm]..

[41] DEFRA BSE Information, Weekly cumulative statistics and New herd statistics.

[42] Veterinary Laboratory Agency, cited in DEFRA BSE Enforcement Bulletin, 62, September 2001.

[43] DEFRA BSE Information, Confirmed cases per million head of cattle population over 24 months of age.

[44] DEFRA BSE Information General statistics – GB.

[45] DEFRA BSE Information General statistics - GB.

[46] DEFRA BSE Information General statistics - GB.

[47] Figures from DEFRA [www.defra.gov.uk/animalh/bse/bse-statistics/level-3-scheme.html]. For details of this programme, see K Taylor, MAFF Programme to Eradicate BSE in the United Kingdom, in The Mad Cow Crisis (S C Ratzan, Ed), UCL Press, London, 1998.

[48] Figures from DEFRA [www.defra.gov.uk/animalh/bse/bse-statistics/level-3-scheme.html]. MAFF gave figures for UK cattle herds as totalling 10.878m head in 2000 (11.281m in 1999, and 11.237m in 1998) Agra Europe Weekly, 30 March 2001. Adult cattle total some 5.3m in 2001, according to the table of figures on testing of animals, FSA Press Release 2001/0132, 3 August 2001.

[49] Figures from DEFRA [www.defra.gov.uk/animalh/bse/bse-statistics/level-3-scheme.html].

[50] J Meikle, The Guardian, 8 February 2002.

[51] DEFRA BSE Information, Suspect cases born on or after 1 January 1996.

[52] DEFRA Statement: A BSE case born in April 1997, August 2001.

[53] BBC Radio 4 Farming Today, 18 June 2001, citing Professor Peter Smith of SEAC.

[54]  Farmers Weekly, 3 March 2000.

[55]  DEFRA, www.defra.gov.uk/animalh/bse/bse-science/level-4-scrapie.html, Incidence of Scrapie.

[56]  DEFRA BSE Information, Other TSEs.

[57]  DEFRA BSE Information, Other TSEs.

[58]  Reuters, Paris, 4 December 2001.

[59]  Reuters and Associated Press, 16 June 2001.

[60]  Irish Times, 15 March 2001.

[61] Agence France Presse, 8 February 2002.

[62]  Department of Health, Monthly CJD Statistics, 4 February 2002.

[63]  Department of Health, Monthly CJD Statistics, 4 February 2002.