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 are the production and economic consequences of anthelmintic resistance (AR) in liver fluke?
• How to develop tools to quantify the economic impact of liver fluke infections at global, national, regional and farm level to support decision-making by governments, animal health organisations and farmers?

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

Current systems use average production estimates and thus lack farm-specificity, even though fluke impacts are highly variable between farms and even within farm territories. Current approaches to economic assessment are also based on partial budgeting and do not reflect the effect on the whole-farm economic performance.

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

• Additional studies to determine the production impact of liver fluke infections in various geographical settings, with inclusion of impacts on fertility.
• Use development of various economic modelling approaches and adapt them to helminth infections.

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

• A closer collaboration between the model‐makers and model‐users and the stimulation to develop concrete business cases may be the critical success‐factor for these systems to become self‐sustainable in the near future.
• Linking economic models to real data collected on farm, rather than economic models that estimate impact based on previous knowledge on productivity impact only.

Existing knowledge including successes and failures

Whereas an increasing amount of data are being generated for the direct production impacts of liver fluke infections, more emphasis should now be given to the production and economic impacts of AR.
Over the last decade, good progress has been made in assessing the production economic impacts of helminths in ruminants, and these have extensively been reviewed in sheep and in cattle. A remaining gap is to establish the impact on fertility parameters using randomized intervention field studies. However, the major challenge is to develop
tools that are able to quantify the economic impact of liver fluke at national, regional and farm level to support decision‐making by various stakeholders and that can be used as management tools.