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?

What is the role of livestock movements and wildlife reservoirs in the spread of liver fluke infection in general and of resistant genotypes in particular?

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

• Effective contact between hosts is a function of grazing shared pasture, with transmission depending on grazing high-risk pasture subsequent to a contamination event and subsequent development and persistence of metacercariae.
• Contact networks in this case become pasture grazing maps allied to topographical and climatic influences on the life cycle. These are complex to construct, farm-specific, and difficult to validate.

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

Need for empirical and theoretical studies at a range of scales to determine how contact through shared grazing drives
transmission and the implications for the spread and development of resistance.

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

• Need more molecular markers of infection and AR.
• Mechanistic rather than only empirical prediction tools.
• More precise ways to capture and record livestock movements within farms.
• Quantification of the role of wildlife in fluke transmission within and between farms.

Existing knowledge including successes and failures

General understanding of the fluke life cycle permits ‘rule-of-thumb’ estimation of duration and level pasture infectivity. This is applied in practice but could be refined by taking a contact network approach, with pastures as nodes.