3. Bovine Tuberculosis and the Control of Possums
The introduced Australian brushtail possum (Trichosurus vulpecula) is a very serious pest in New Zealand. It causes extensive damage to indigenous forests and acts as the major vector of bovine Tb to cattle and deer.
Forest ecosystems are being drastically altered by the selective attention of possums that can eliminate favoured browse-species from whole tracts of forest. Possums also prey on birds.
Any restrictions on access for meat and dairy products were imposed by our trading partners due to the presence of bovine Tb could potentially reduce returns from agricultural production by up to $500 million annually.
Currently about $45 million is spent annually on poisoning and trapping possums. However, this level of expenditure is not sustainable and these methods of control are becoming less socially and politically acceptable. Around $15 million is spent annually on research into control of possums and bovine Tb.
Research into possum biocontrol as a long-term cost-effective solution to the possum problem was initiated in 1993. The expectation is, however, that control will be, for the foreseeable future, dependent on a number of technologies used in an integrated manner.
The research into biological control of possums, funded through Vote: Agriculture was initiated following a National Science Strategy Committee (NSSC) meeting, held in October 1992, at which clear research priorities for biological control were established. Priorities were reviewed at NSSC workshops in 1995, 1997, 1999 and 2001.
The NSSC has now been transformed from the previous ministerial committee to a committee reporting to the Board of the Foundation for Research Science and Technology; with that rearrangement of responsibilities, all the research programmes except the Bovine Tb work, have now been transferred to the Foundation for Research, Science and Technology for assessment and funding.
3.1 PBC 258
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Programme Title: |
Immunology of Bovine Tuberculosis (2003-04) |
Programme Leader: |
Dr Bryce Buddle |
Institution: |
AgResearch CRI |
Programme Goal and Rationale: Develop and evaluate diagnostic tests and vaccines for control of bovine tuberculosis in cattle and possums. Develop vaccine delivery systems for possum biocontrol vaccines.
Objective 1
Objective Title: |
Immunology of bovine tuberculosis |
Research Leader: |
Dr Bryce Buddle |
Description:
Aims: Develop and evaluate diagnostic tests and vaccines for control of bovine tuberculosis in cattle and possums. Develop vaccine delivery systems for possum biocontrol vaccines.
- Determine whether the cervical skin test response to PPD in Mycobacterium bovis-infected cattle can be enhanced by adding the following proteins to PPD:
- GM-CSF;
- Other immunomodulatory agents which work by stimulating through Toll receptors (e.g. CpG).
- Identify chemokines/cytokines in skin test reaction site via micro array analysis to provide an understanding of the immunological processes involved in the tuberculin skin test response.
- Determine whether GM-CSF enhances the production of IFN- in the whole blood IFN- test and if so whether addition of GM-CSF can increase the sensitivity and/or specificity of the test.
- Determine whether cattle which have ingested oral bait BCG vaccines produce a positive response in the caudal fold skin test, comparative cervical skin test or whole blood IFN- test and determine whether these cattle are protected against bovine tuberculosis (to be funded 50% by MAF; and 50% by AHB - objective approved).
- Determine whether possums that have consumed oral bait BCG vaccines shed BCG in their faeces; determine how long BCG persists in their tissues and generation of mucosal and systemic immune responses. Determine how long the BCG persists in the faeces when kept under natural environmental conditions (to be funded 50% by MAF; and 50% by AHB - objective approved except for section on BCG persistence in faeces, which is still pending).
- Determine the effectiveness of feeding possums multiple doses of oral bait BCG vaccine on one occasion or spread over 5 consecutive days for protection against bovine tuberculosis (to be funded 75% by MAF; and 25% by AHB - with objective currently being considered by AHB).
- Identify areas for undertaking a field trial to test the efficacy of oral bait BCG vaccine in wild possums (collaboration with Landcare, in consultation with AHB who would be funding all the Landcare component - currently being considered byAHB; AgResearch component to be 100% funded by MAF).
- Determine the pH of the possum stomach and test two preparations for their ability to reduce stomach acidity to prevent degradation of oral bait tuberculosis vaccines in the stomach.
- Determine whether a model antigen or ZP3 can be cross linked to BCG to produce a combined tuberculosis/biocontrol vaccine.
- Set up mouse model for testing oral adjuvants and compare activity of three putative novel mucosal adjuvants with cholera toxin.
- Submit three papers to refereed journals.
Contact for Enquiries
Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0623
Fax: +64 4 894 0741
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