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Protective immunity and competitive exclusion in development of effective intervention products for poultry - OZ0606

Campylobacter jejuni is the most common foodborne bacterial cause of human acute enteritis. Because of the ubiquitous nature of this organism in the environment the food sources of this infection remain debatable. Nevertheless, the handling and consumption of raw, or undercooked, poultry meat is considered a significant risk factor. Up to 90% of poultry flocks in the United Kingdom are colonised asymptomatically with this organism. The reduction or elimination of poultry colonisation, in order to reduce the risk of human infection, has been recommended by the ACMSF. With the application of molecular epidemiological methods the sources and routes of poultry flock infection are now being understood. Infection appears to enter the poultry house horizontally from surrounding environmental contamination. Chickens tend to remain uncolonised for the first 2-3 weeks of life (the lag phase). Thereafter colonisation, once initiated, is transmitted extremely rapidly to 100% of birds and induces very significant bacterial levels in the caeca. All the evidence suggests that control of colonisation must involve prevention of the initial infection rather than control of transmission through the flock. To date a multi-layered research approach has been adopted. Initially biosecurity is enhanced to reduce bacteria entering the flock. However, the level of biosecurity required has so far proved to be impractical to maintain to reliably produce negative flocks at slaughter. Supplementary measures are, therefore, required to enhance avian resistance to this initial infection. Two such measures are investigated in this project (I) vaccination and (ii) competitive exclusion. Preliminary work has been undertaken on both approaches in previous projects. These results indicate that further information is urgently required on the bacterial and host factors affecting colonisation; the basis for the lag phase; the factors affecting immune responsiveness to campylobacter antigens and the identification of suitable competitive exclusion agents of C.jejuni colonisation.
Obj. No. Completed by date Description
01 31/03/04 To identify bacterial factors essential for avian gut colonisation
02 31/03/03 To validate the lag phase and investigate the underlying mechanism
03 31/03/04 To investigate the factors affecting the efficacy of immune responsiveness of poultry to campylobacter antigens
04 31/03/04 To identify homologous and heterologous micro-organisms with efficacy as competitive exclusion agents

Project Documents
• Final Report : Protective immunity and competitive exclusion in development of effective intervention products for poultry   (202k)
Time-Scale and Cost
From: 2001

To: 2004

Cost: £232,145
Contractor / Funded Organisations
Veterinary Laboratories Agency
Animal Health              
GM Non-Food              
Plants and Animals              
Fields of Study
Animal Health