Roadmap for the development of control strategies for liver fluke

What are we trying to achieve and why? What is the problem we are trying to solve?

Prevent the introduction of F. hepatica and/or resistant parasites onto farms where either are not already present.

What are the scientific and technological challenges (knowledge gaps needing to be addressed)?

• The degree to which AR develops on each farm versus its introduction with purchased animals.
• How effective quarantine measures can be against liver fluke and AR.
• Farmers’ willingness to adopt quarantine measures, and how these should be designed: length of time of isolation, identification of appropriate pasture risk for turnout.

What approaches could/should be taken to address the research question?

• Field and modelling studies to document and increase efficacy of quarantine procedures on livestock imported onto farms.
• Population genetic approaches to evaluate relative importance of AR spread between farms versus on-farm selection, following recent approaches for nematodes.

What else needs to be done before we can solve this need?

• Pen-side diagnosis of fluke infection and AR.
• Better understanding of the genetics of resistance in liver fluke.

Existing knowledge including successes and failures

• Solid field evidence for the effectiveness of different strategies to limit AR spread and development is lacking.
• For trematodes, complex genetics (ploidy) and involvement of intermediate host in which clonal expansion occurs make population genetics even more difficult than in nematodes.
• Cost of quarantining and testing animals being brought in to the farm might limit practical application.