Review of the Food-borne Zoonoses Research ... - ARCHIVE: Defra

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thinning process for molecular tracking to elucidate the most important sources associated with flock colonisation. In addition, the whole chain of events from farm through to the slaughter process will be followed in a separate study to investigate the sources of infection and contribution to Campylobacter load associated with clearance and transport. A number of exposure experiments will also be carried out in Objective 3 to investigate the survival and colonisation potential of environmental strains. All of the above work will provide good quality data with which to update the VLA risk assessment model (Objective 4). Review Summary OZ0608 was an ambitious project which has moved our understanding of the environmental sources of Campylobacter on the poultry farm forward considerably. The team also developed a PCR screening test for strain-specific detection of Campylobacter, enabling detection of the organism where traditional methods failed. While there were data deficiencies in the Quantitative Risk Assessment, it proved useful in the development of practical interventions, and data gathered from OZ0610 and OZ0613 will be used to update the model. Following on from OZ0608, project OZ0610 aims to investigate the role of environmental survival, reservoirs of infection, and recycling systems, both on or entering the farm, in the colonisation of broiler flocks with C. jejuni. A vast amount of data has been collected by the team, which has yet to be fully analysed, in order to identify badly needed intervention measures for the poultry industry. Building on both OZ0608 and OZ0610, project OZ0613 will continue to advance knowledge of the farm situation, environmental stresses, and seasonality that may adversely affect campylobacters and be used in control. The project includes the first UK survey of campylobacters in broilers at slaughter meeting recommendations of the Advisory Committee on the Microbiological Safety of Food, and the EU requirement for a survey from January 2008. It is anticipated that this project will significantly contribute to the campylobacter evidence base and provide valuable data on which future costeffective controls can be based. All three projects in this cluster have benefited from a close working relationship with the FSA and industry. Such collaboration is also invaluable in ensuring findings and recommendations from research projects are implemented on farms. 82
Project code: OZ0609 Project title: Determining the role of maternal antibodies in the lag phase of Campylobacter jejuni infection in chickens. Start date (dd/mm/yy): 01/05/2005 End date (dd/mm/yy): 31/05/2006 £50,012 Total cost: Affiliation: Veterinary Laboratories Agency Sub-contractor(s): Abstract of research Campylobacter jejuni is the leading cause of bacterial enteritis in the UK. The handling and/or consumption of contaminated poultry meat is believed to be a risk factor. The avian intestine is considered the natural environment for the organism, and up to 90% of poultry flocks in the UK are colonised asymptomatically. Thus, reduction or elimination of the organism in poultry in order to reduce the number of human cases is an objective of DEFRA and FSA. A number of intervention strategies have been proposed, including increased bio-security, vaccination and competitive exclusion. Increased bio-security alone has so far failed to consistently reduce the extent of colonisation, so a multipronged approach would seem to offer the most promise. Commercial birds tend to exhibit a lag-phase of infection, wherein they usually remain uncolonised during the first 2-3 weeks of life. Thereafter the organism spreads rapidly through the flock. The lagphase represents a window-of-opportunity to apply intervention strategies. Moreover, understanding the under-lying mechanisms could help in the development of successful strategies. One likely contributory factor to the lag-phase, maternally-derived immunity, was investigated. Previous DEFRA-funded work indicated that the susceptibility of commercial birds to colonisation is inversely proportional to the levels of anti-C. jejuni antibodies present in the chicks. These antibodies are vertically transmitted from infected breeder hens. Their levels decline to background during the first 3-4 weeks of life. The role of maternal immunity was studied by looking at the susceptibilities to colonisation of chicks derived from SPF and commercial flocks and from experimental hens colonised and uncolonised by C. jejuni. Review summary The role of the humoral antibody response, including passive transfer of maternal antibodies, remains unclear, making development of a vaccine to prevent poultry colonisation with Campylobacter more difficult. This project has contributed to filling this knowledge gap, confirming that maternal antibodies play a role in the colonisation lag phase, but that other unknown factors are also involved. It has also shown that any exposure of very young chicks to campylobacter will result in colonisation. The results of this work have assisted in formulation of policy, suggesting that attempting to keep breeding stock free of campylobacter may not be a useful strategy in the effort to reduce human campylobacteriosis. 83
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Contents Section A - Introduction..
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Review of the Food-borne Zoonoses (
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Plans for taking forward these prio
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Policy Objectives The key policy ob
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Figure 2. Laboratory reports of Sal
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Figure 4. Laboratory reports of Cam
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6. Aims of the FBZ research review
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Section B - Review Summaries 16
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epidemiology of Salmonella and anti
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There is a need to objectively asse
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2. Campylobacter review summary 2.1
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for this organism. Research within
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3. E. coli review summary 3.1 Succe
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4. Other zoonotic pathogens of inte
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Annex 1 - Projects Reviewed 30
Page 32 and 33: OZ0311 Conventional versus capillar
Page 34 and 35: OZ0402 OZ0404 OZ0405 OZ0407 OZ0604
Page 36 and 37: OZ0704 OZ0705 OZ0706 OZ0707 Quantif
Page 38 and 39: Annex 2 - Project Abstracts and Pro
Page 40 and 41: To test the suitability of the AFLP
Page 42 and 43: Project code: OZ0324 Project title:
Page 46 and 47: Review Summary The knowledge that t
Page 48 and 49: Review Summary The project was felt
Page 52 and 53: It is clear that the EC legislative
Page 54 and 55: if the vaccines currently available
Page 56 and 57: Four published papers have come out
Page 58 and 59: Review Summary This epidemiological
Page 60 and 61: Project code: OZO316 Project title:
Page 64 and 65: agricultural industry/public health
Page 66 and 67: testing laboratories. In addition,
Page 68 and 69: animal pathogen but is a human path
Page 70 and 71: esearch has also substantially impr
Page 72 and 73: to elucidate the antigenic repertoi
Page 74 and 75: and have contributed to our underst
Page 76 and 77: Fundamental issues concerning the f
Page 78 and 79: Review summary Project OZ0606 focus
Page 80 and 81: Abstract of research OZ0608 The ado
Page 84 and 85: Project code: LK0665 Project title:
Page 86 and 87: Review summary While poultry meat i
Page 88 and 89: Review summary A key aim of this pr
Page 90 and 91: Review summary This project aimed t
Page 96 and 97: Project code: OZ0138C Project title
Page 102 and 103: Abstract of research Projects OZ070
Page 104 and 105: produced were both relevant and imp
Page 106 and 107: List of External Reviewers. Mr. Pau
Page 108 and 109: Review of Defra’s FBZ Research Pr
Page 110 and 111: Review of Defra’s FBZ Research Pr
Page 112 and 113: Annex 5 - Review Timetable 112
Page 114 and 115: 11.45 - 12.00 Bovine and Porcine Fo
Page 116: Campylobacter Other 11.50 - 12.05 P
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