Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Kawasaki disease wikipedia , lookup
Childhood immunizations in the United States wikipedia , lookup
Infection control wikipedia , lookup
Rheumatoid arthritis wikipedia , lookup
Transmission (medicine) wikipedia , lookup
African trypanosomiasis wikipedia , lookup
Sociality and disease transmission wikipedia , lookup
Germ theory of disease wikipedia , lookup
Department for Environment Food and Rural Affairs Consultation on the transposition of Council Directive 2002/99/EC on Meat Hygiene January 2007 Veterinary Risk Assessment Veterinary Advice on the Likelihood of Transmission of Disease Arising from the Different Options for the Transposition of the EU Council Directive 2002 (2002/99/EC) Executive summary 1. It is important to note that in the context of this Directive, the hazard is most correctly the infectious agent of the specified disease contaminating the meat e.g. foot and mouth disease virus or african swine fever virus; however, for risk management purposes it may more appropriately be considered to be the meat originating from a protection (PZ) or surveillance zones (SZ). 2. The risk of disease transmission arises from the ingestion by other animals of the meat produced from viraemic animals with un-disclosed disease, within the PZ and SZ surrounding an infected premises (IP). 3. The critical control points to reduce the likelihood of the spread of the hazard are: a) The stamping of meat and meat products from a PZ or SZ with the appropriate health mark, without which the meat would become indistinguishable from meat not originating from the PZ and SZ . b) The monitoring and enforcement of treatment standards. c) The monitoring and enforcement of checks on both stamped and unstamped fresh meat. 4. The critical control point for the reduction of the likelihood of transmission of disease from meat is one or more of the appropriate treatment as described in annex II of Council Directive 2002/99/EC. 5. It should be noted that if the product has been treated using one of the proscribed approved methods, the likelihood of viable virus being present should be negligible. Stamping of meat will achieve no further reduction in disease risk, but will enhance traceability of the product if there has been a failure of the treatment regime. 6. Veterinary advice is that the controls described in option two are the most likely to prevent additional outbreaks of disease within the UK. These could occur many months after the initial incident, resulting from infected meat products stored within the production and supply chain. 7. The source of one IP is the spread from another; and when this Directive is enforced in all EU Member States (MS), there is thus a mutual benefit, as it will reduce the risk of UK importing infection from the PZ and SZ of IPs in other MSs as it will allow the identification of meat from these areas and facilitate the enforcement of treatment standards. 1 Introduction 8. The aim of the rules in 2002/99/EC is to prevent the introduction or spread of animal diseases resulting from the placing on the market of products of animal origin (POAO) originating from a holding or area infected by epizootic diseases and the obligation to subject products coming from PZ or SZ areas to treatment to destroy the disease agent. 9. The risk of disease transmission arises from meat produced from viraemic animals, with un-disclosed disease, in the protection (PZ) and surveillance zones (SZ) surrounding an infected premises (IP). 10. The agents of interest in this context are those for: a) Rinderpest (RP). b) Peste de petit ruminants (PPR). c) African swine fever (ASF). d) Swine vesicular disease (SVD). e) Newcastle disease (ND). f) Classical Swine Fever (CSF) g) Please note that foot and mouth disease (FMD) and avian influenza (AI) are dealt with in separate legislation. 11. For the purpose of this risk assessment, it is assumed that disease is present on at least one GB premises (IP) and has been detected (until the outbreak has been detected, the legislation could not be used. Therefore, it does not consider a release assessment for any of the diseases, but concentrates on exposure and consequence assessment. 12. This veterinary advice considers the risk arising from the movement and potential consumption of meat or meat products from the surrounding SZ or PZ of an infected premises (IP). 13. The source of one IP is the spread from another; and when this Directive is enforced in all EU Member States (MS), there is thus a mutual benefit, as it will reduce the risk of UK importing infection in untreated meat originating from the PZ and SZ of IPs in other MS’s. Hazard identification 14. For risk management purposes the hazard may more appropriately be considered to be the meat originating from a protection (PZ) or surveillance zones (SZ), rather than the infectious agent of the specified disease contaminating possibly contaminating the meat. 2 Figure 1: H4 - Stages of meat production and processing subject to official control Cold Store Cutting Plant Co-located with Meat Processing plant Abattoir Meat Processing Plant (Cooked) Cutting Plant Co-located with abattoir MHS control LA control 3 Control ceases The options considered in this document a) Option 1: Do nothing; do not implement any control measures. b) Option 2: Transpose the Directive exactly. c) Option 3: Impose restrictions on products of animal origin from PZs and SZs.. The risk question addressed in this document 15. How effective are the specified three options in reducing the likelihood of disease transmission via meat produced from animals in the SZ or PZ to other susceptible livestock? 16. Based on the hazard being the meat originating in a PZ or SZ, this veterinary risk assessment has been simplified to consider the risk due to CSF only. 17. CSF has been selected because historical records and disease risk modelling have shown that CSF is the most likely of the diseases to cause an outbreak in UK, the CSF virus has the following characteristics: a) Widely distributed in the carcase of an infected animal. b) Infectious by the oral route. c) Has a very low oral infectious dose. d) Capable of surviving for extended periods in some meat and meat products. e) Relatively stable and resistant to disinfection. 18. CSF is thus the disease most likely to give rise to outbreaks as a result of “leaks” from the system of controls required by 2002/99/EC. Summary of the major risk factors for the transmission of disease to susceptible species: Disease related risk factors 19. The following disease related risk factors will have an effect on the likelihood of transmission of disease to susceptible animals: a) It is important to note that the likelihood of transmission of disease from the movement of meat or meat products is orders of magnitude less than that resulting from the movement of infected live animals. b) The CSF virus is resistant to disinfection and can survive for considerable periods of time in the environment and in uncooked and preserved meats, such as salami and ham. c) CSF can be transmitted orally and the oral infectious dose is extremely low. Susceptible host related risk factors 20. The following susceptible host related risk factors will have an effect on the likelihood of transmission of disease to susceptible animals: 4 a) The source of the risk is meat and meat products, thus infection would have to be by the oral route i.e. they would have to be eaten. b) Therefore, the ban on swill feeding is significant. c) Behavioural studies have shown that herbivores such as cattle and sheep are unlikely to consume meat products, unless they have been transformed in some way (e.g. minced and mixed with other feed). d) The need for oral consumption of the product therefore restricts the likely susceptible population to pigs or poultry. e) The risk diseases of relevance to H4 are mainly those diseases that affect pigs. Animal management related risk factors 21. The following animal management related risk factors will have an effect on the likelihood of transmission of disease to susceptible animals: a) The geographical distribution of the industry in UK b) The ban on swill feeding. c) CSF is not windborne over substantial distances. d) Movement controls: Identification, registration of premises and stringent movement controls for live pigs. e) The centralised control of the industry and the general high standards of husbandry and management. f) The vertical integration of the intensive productions systems (production pyramid) and the absence of markets. g) The age batching of pigs in the production process. h) The high-level so biosecurity present in the industry. i) The high levels of health and production monitoring which are the norm in the industry. j) Ante and post-mortem inspection at slaughter. k) Wild boar which are the main wildlife host for CSF in Europe, are currently present in the UK in very restricted areas, at relatively small population densities; however, it would be possible for an isolated wild boar population to become infected, maintain that infection and for this to spill over to commercial pig herds; especially if these are managed outside as free-range units. l) The number of backyard and pet pigs are currently not well known, however, it is likely that these are small in number and dispersed. Although legislation forbids feeding such animals using catering and household waste (swill), the lack of knowledge of their keepers makes them a potentially a serious source of disease risk. Product management related risk factors 22. The following product management related risk factors will have an effect on the likelihood of transmission of disease to susceptible animals: 5 a) The health marking of the meat or meat product to indicate that it originated from a PZ or SZ. b) Treatment of the product as per annex III of Council Directive 2002/99/EC. c) Official controls. Summary of the risk management options Managing the disease agent related risk factors 23. The disease related risk factors can be managed by managing the agent through treatment of the product and avoiding the risk of contact between pigs and untreated product. Managing the susceptible host related risk factors 24. As discussed above, susceptibility of the host population is determined by behaviour. The implementation and enforcement of the swill feeding ban is important in reducing the risk of disease transmission. Managing the animal management related risk factors 25. The normal management practices described above that are inherent within the UK pig industry mitigate much of the risk. However, three important risks require to be managed: (i) outdoor pigs, (ii) wild boar and (iii) back-yard/pet pigs. The most important aid to mitigation of the risk in this class is increasing public education and awareness of: a) the need to register pigs and their movement and b) the dangers (and illegality) of feeding both food fit for human consumption and food waste to pigs. Managing the product management risk factors Discussion of the risk management options 26. If there are no restrictions on meat or meat products the scale of the outbreak is likely to be of an unpredictably longer duration and to be more dispersed geographically. a) The increased duration may be particularly unpredictable and outbreaks sporadic due to the ability of CSF to survive for considerable periods of time in uncooked or preserved meats that may sit in the food chain for many months. b) However, it is important to note that in order to pose a risk, the meat has to be eaten by a pig. Introduction to the pig population by the route of meat and meat products originating in a PZ or SZ is likely to be restricted to: Outdoor pigs illegally fed “over the fence”. Scavenging wild-boar. Back-yard / pet pigs that are illegally fed kitchen waste. 6 c) Back-yard / pet pigs are likely to give rise to isolated outbreaks or may even fail to pass on infection to other pigs due to the lack of opportunity. Scavenging wildboar could potentially maintain infection independently; which would then only become apparent if it spilled over into commercial pigs. 27. Introduction of disease to the intensive, indoor pig production sector is unlikely for the reasons discussed above. Scale of outbreak – directive/ H4 implemented with option 2 controls. 28. If option two controls are imposed, the scale of the outbreak will be independent of the movement on meat, and will influenced only by other factors. a) Adherence to option 2 controls would reduce to negligible the risk to both UK and other MS’s from uncooked or preserved meat. The risk remains negligible rather than zero due to the possibility of illegal movement of meat outside official controls. b) All residual risk to UK and other MS is negated by full implementation and enforcement of the ban on swill feeding. Scale of outbreak – directive/ H4 implemented with option 3 controls 29. If option three controls are implemented, this would expose the UK to the same level of risk as option 1, but would protect export markets to the same extent as option 2. Conclusions and recommendations 30. Veterinary advice is that the controls described in option two are the most likely to prevent additional outbreaks of disease within the UK. These have the potential to occur many months after the initial incident (especially in the case of resistant infectious agents such as CSF virus), resulting from infected meat products stored within the production and supply chain. 31. The critical control point for the reduction of the likelihood of transmission of disease from meat and meat products is the appropriate treatment as described in annex II of Council Directive 2002/99/EC. 32. Veterinary advice is that the critical control points to reduce the likelihood of the spread of the hazard are: c) The stamping of fresh meat from a PZ or SZ with the appropriate health mark, without which the meat would become indistinguishable from meat not originating from the PZ and SZ. d) The monitoring and enforcement of treatment standards, and official controls. e) The monitoring and enforcement of checks for both stamped and unstamped fresh meat outside the production chain. 33. It should be noted that if the product has been treated using one of the proscribed approved methods, the likelihood of viable virus should be negligible. Stamping of such 7 meat products will achieve no further reduction in disease risk, but will enhance traceability if there has been a failure of the treatment regime. Andrew Paterson AHTBD 16 June 2006 8