Roadmap for development of diagnostic tests for helminths

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

Rapid, cost-effective, pen-side and/or laboratory-based diagnosis of infection, including the level of infection and morbidity and the presence of AR, threshold for economically relevant infection levels to enable targeted and evidence-based treatment and control strategies.

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

• Lack of accurate, sensitive,rapid and cost effective tests to quantify herd level infection intensities, morbidity, production impacts and anthelmintic resistance status of fluke and GI nematode infections
• Inability to easily identify individual animals needing treatment or other interventions
• Lack of rapid tests for acute disease syndromes or risks. eg. acute fluke infection in sheep or inhibited nematode larvae
• Economic constraints due to low revenues in livestock particularly small ruminant farming and thus only very limited financial capacity for diagnostics

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

• Develop biomarkers (parasite and host) such as liver proteins, regulatory hormones, secreted parasite molecules for diagnosis on non -invasive sample matrices.
• Develop molecular genetic tests for drug resistant parasites
• Develop scalable, rapid and affordable diagnostic platforms for laboratory-based and penside tests.
• Develop sensors and wearable technologies that can be implanted directly in or on the animals or in the environment (barn or pasture)
• Develop genetic tests to assess the susceptibility/resilience of individual animals
• Establish meaningful/informative group or flock diagnostic approaches
• Further develop automated coproscopic analysis tools

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

• Improve genomic resources and diagnostic platforms for both host (i.e. genetics) and helminths
• Improve understanding of host immune responses to helminths (including antigen and antibody identification)
• Improve understanding of molecular mechanisms of drug resistance
• Improve understanding of appropriate diagnostic platforms
• Develop criteria and methodologies for rigorous validation of tests

Existing knowledge including successes and failures

Accurate, quick and simple quantitative diagnosis of helminth infection is needed to allow evidence-based parasite control, targeted treatments, better surveillance, monitoring and anthelmintic stewardship. However most current diagnostics depend on microscopic detection of eggs or helminth‐specific antigen in faeces, or detection of antibody in serum or milk. All of these assays have limitations in accuracy and sensitivity and results are normally only available to farmers several days after the sample has been collected.
All these assays have specific limitations, for example, antibody tests may detect historic infection. Furthermore, as individual animal tests they are usually to costly for routine infection monitoring. Significant advances have been made in the development of web-based and semi-automated coproscopic tools.