Research/Virulence genes and pathogenicity of P. multocida
From Poultry Hub
Title: Confirmation of virulence genes and pathogenetic mechanisms of Pasteurella multocida in chickens
Project Leader: Ian Wilkie at UQ funded by Poultry CRC (Project 03-13)
Duration of Project: Now completed (1 July 2003 to 30 December 2005)
Contents |
Project overview
Pasteurella multocida continues to be a major infectious agent of poultry throughout the world, causing chronic disease problems in intensively managed birds, and outbreaks of acute, fatal disease in poultry kept under free-range and open management systems. Current vaccines offer little protection and have undesirable side-effects due to their reliance on adjuvants. A solid immunity may be invoked by ‘live’ vaccines, but these are cumbersome to administer and sometimes cause significant disease in vaccinated flocks. All available evidence shows that good immunity is invoked by substances only produced by bacteria growing in vivo.
Project objectives
- Elucidate genes of P. multocida involved in causing disease (some or all of the products of these genes may be involved in immunity and are therefore excellent vaccine candidates); and
- Investigate the early immune responses of chickens to lethal and non-lethal infection by comparing specific cytokine responses within the first 24 hours.
Project progress
This project has been completed and the Final Report is available from the Poultry CRC (ISBN: 1 921010 10 X).
The project identified a number of genes which appear to be necessary for the establishment, growth, or reproduction of P. multocida within its bird hosts. Vaccine trials using P. multocida gene products as likely antibody targets failed to identify any that warranted development as putative vaccines. The second line of research involving the chemical signals (known as cytokines) by which the immune system regulates its responses to infection was not completed due to lack of access to animal housing of suitable containment level. If this becomes available, this work will be finalised and results published.
