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Bovine Spongiform Encepalopathy, BSE

Bovine Spongiform Encepalopathy, BSE. Should FAO have maintained its silence?. Why did FAO sound the alert?. Active surveillance for BSE introduced by some infected countries indicated higher rates of infection than previously thought

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Bovine Spongiform Encepalopathy, BSE

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  1. Bovine SpongiformEncepalopathy, BSE Should FAO have maintained its silence?

  2. Why did FAO sound the alert? • Active surveillance for BSE introduced by some infected countries indicated higher rates of infection than previously thought • By end 2000, beginning 2001 BSE was discovered in major EU countries so far having denied possibility if infection • The EU is a major global exporter of cattle and by-products

  3. Up to 1987 1989 - 1994 1995 - 1999 2000, 2001 1997 1989 1990 1991 2001 1994 2000 Years of first report of native BSE Portugal reported BSE in imported cattle in 1990

  4. Year of birth of earliest case • UK: 1973/74 • FRANCE, IRELAND: 1981 • SWITZERLAND, PORTUGAL: 1984 • BELGIUM, NETHERLANDS: 1993 • GERMANY: 1994 • DENMARK: 1996

  5. Means of spread • Meat and bone meal (MBM) regarded as most important means of spread • Free trade in the EU facilitated spread of BSE at a time, when the disease had not even been recognized • Recycling of bovine tissues as feed led to amplification

  6. Epidemiology of BSE Evidence of amplification: France, Portugal, Switzerland

  7. BSE Risks • Risk of Importation: BSE in imported cattle and in homebred cattle fed imported infective material • Risk of amplification: Propagation of BSE through recycling of animal by-products in susceptible species • Risk to humans: vCJD probably through consumption of infective material of bovine origin

  8. Countries at risk of BSE in native livestock those that have: • imported live cattle originating from affected countries or • imported meat meal containing infective tissue and • recycle ruminant by-products in ruminants

  9. Cattle Exports from UK Importing Region EC-SSC considered 5% of birth cohort born between 1988 and 1993 in UK infected

  10. Cattle Exports from W-Europe Importing Region

  11. Global trade in MBM Metric tons

  12. Exports of MBM by Region Metric tons

  13. Imports from other region Metric tons

  14. Trade Matrix of MBM (1996-99) Exporter Metric tons Importer

  15. EU Regional Risk Analysis • Qualitative analysis based on • External challenge: likelihood and amount of BSE agent entering into a defined geographical area • Stability: the ability of a BSE/cattle system to prevent the introduction and to reduce the spread of the BSE agent within its borders • not feeding MBM to cattle • rendering system (133/20/3) • SRM removal • Interactions of the above

  16. Epidemiology of BSE

  17. Not done Highly unlikely Unlikely Likely or lower level Confirmed at higher level EU-Geographic BSE Risk Analysis

  18. Problems in Risk Quantification • Meat meals are not differentiated in trade statistics (pig, poultry, fish, cattle) • Cross-contamination of meat meals and livestock feeds • Differences in ‘riskiness’ of MBMs by country and period • Triangular trade • Compound feed

  19. BSE Risk in other Species • TSEs occur in most species • BSE shown to be able to infect a number of wild ungulates (in zoos) • BSE shown to be infective for cats • Transmission to sheep a distinct possibility • Oral transmission to pigs and poultry so far not successful

  20. Uncertainties/Unknowns • Cause: Novel infectious agent, PRION, but this is disputed by some scientists • Origin of BSE-Prion: Main hypothesis is crossing of species-barrier by scrapie agent, but alternative hypotheses exist • Transmission: Feed generally accepted as main vehicle, but vertical and horizontal transmission not excluded

  21. Uncertainties/Unknowns • Infection: Single exposure vs cumulative effect • Genetic component: is susceptibility linked to certain genotypes? • Diagnostic test for live animals: Is it possible to develop and how long will it take? • Etc, etc, etc....

  22. The Risk Manager’s Dilemma ‘Can we know the risks we face now and in the future?’ ‘No, we cannot, but yes, we must act as if we do!!!’ ‘Science will not provide all the answers!’

  23. FAO recommends • National Risk Analysis to determine own risk status • Surveillance for BSE in cattle at risk of having been exposed to infective material • Restriction of MBM in ruminant feed • Banning of Specified Risk Materials and fallen stock from MBM • Stricter Feed and Meat industry regulation and enforcement thereof

  24. Information on BSE

  25. EU measures to tackle BSE • A ban on the feeding of mammalian meat and bone meal (MBM) to cattle, sheep and goats, as of July 1994; • Higher processing standards for the treatment of animal waste (133 degrees, 3 bars of pressure for twenty minutes) to reduce infectivity to a minimum, as of 1 April 1997; • Active surveillance measures for the detection, control and eradication of BSE, as of 1 May 1998 and the introduction of post-mortem testing from 1 January 2001; • The requirement to remove specified high-risk materials (SRMs like spinal cord, brain, eyes, tonsils, parts of the intestines) from cattle, sheep and goats throughout the EU from 1 October 2000 from the human and animal food chains. • The introduction of targeted testing for BSE, with a focus on high risk animal categories, from 1 January 2001. This measure will be reviewed and extended to all cattle aged over 30 months entering the food chain from 1 July 2001; • The prohibition of dead animals not fit for human consumption to be used for feed production as from 1 March 2001 onwards. • In addition there are country specific measures in force in several Member States, especially those with the highest incidence of BSE. • A ban on MBM to all farm animals and fishmeal to ruminants, from 1 Jan 2001

  26. Proposed draft code of practice on safe animal feeding GENERAL PRINCIPLES AND REQUIREMENTS RAW MATERIALS, MINERALS, VITAMINS AND FEED ADDITIVES • Raw materials of animal, plant and/or marine origin should be obtained from reputable sources, preferably with a supplier warranty...... LABELLING • Labelling requirements shall ensure traceability for all feedingstuffs of their origin, full labelling of ingredients, the correct use of permitted additives..... TRACEABILITY AND RECORD KEEPING • Traceability of raw materials, minerals, vitamins and feed additives in feedingstuffs should be ensured by proper labelling and record keeping.... INSPECTION AND CONTROL PROCEDURES • Official regulatory programmes should be established....

  27. Proposed draft code of practice on safe animal feeding HEALTH HAZARDS ASSOCIATED WITH ANIMAL FEED • It is essential that the levels of hazardous substances in feed are sufficiently low.... Feed Additives • Feed additives should be assessed for safety and approved under stated conditions of use...... Antibiotics should not be used in feedingstuffs for growth promoting purposes in the absence of public health safety assessment.... Feed materials • Feed materials contaminated with mycotoxins in excess of established national maximum levels or international maximum levels established should not be fed to animals..... Feedingstuffs • Feedingstuffs may be marketed only if they are wholesome, unadulterated and of merchantable quality.... Undesirable Substances • Undesirable substances such as pesticides, agricultural and industrial chemicals, heavy metals, radionuclides, zoonoses, mycotoxins, and other microbiological contamination of feedingstuffs should be minimized......

  28. Proposed draft code of practice on safe animal feeding INDUSTRIAL PRODUCTION OF ANIMAL FEEDINGSTUFFS • The producer or manufacturer should establish quality assurance systems based on the principles of Good Manufacturing Practice (GMP). The HACCP principles, as annexed to the Codex “Recommended International Code of Practice - General Principles of Food Hygiene” 5 should be preferred.... ON-FARM PRODUCTION AND USE OF FEEDINGSTUFFS • [To be developed, including provisions for HACCP]

  29. AGA Technical Support to Codex Code of Practice INDUSTRIAL PRODUCTION OF ANIMAL FEEDINGSTUFFS • Good Manufacturing Practice (GMP) based on HACCP ON-FARM PRODUCTION AND USE OF FEEDINGSTUFFS • GMPs for dairy production • GMPs for pig production • GMPs for poultry • Intensive pasture-based systems

  30. HACCP for the Feed Industry • Raw materials • Feed mill • Transport • On-farm • Slaughter • Treatment of by-products (rendering) • Meat

  31. Possible FAO Actions • Mechanisms to assist countries in national risk assessments • Development of appropriate risk management options, including.... • HACCP for the feed industry • GMPs for on-farm practice • Support of capacity building for BSE surveillance and control

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