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?

To develop cost effective, multispecies, quantitative and laboratory-based and point-of-care assays to detect antigens excreted from the host during helminth infection in biological samples? Eg faeces, saliva, urine, milk.

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

• Lack of fundamental knowledge of the parasite and host antigens excreted from the host at different stages of infection for the different helminth species.
• Need for there to be a quantitative relationship between excreted antigen(s) and helminth infection intensities and/or disease and production impacts.
• Antigens need to be species- and stage-specific

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

• Development of antigen capture / immunoassays to detect helminth species and stage- specific antigens excreted in biological material convenient for sampling eg. faeces, milk, saliva etc.
• Develop protein-biochemistry detection tools such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling to allow multi-species detection and differentiation by the analysis of a single crude protein extract.
• Investigate helminth molecule classes, other than antigens, excreted from such as microRNAs, DNA, exosomes, EVs and metabolites in circulation or faeces.
• Development of point of care diagnostic platforms for antigen detection

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

• Well annotated and assembled reference genome sequences and proteomic datasets for antigen mining and characterisation
• Fundamental research on antigens and other molecules secreted by the different helminth species and relased from the host such as proteins, peptides, extracellular vesicles, microRNAs, DNA and metabolites in circulation or faeces
• Development of optimal sample preparation methods.

Existing knowledge including successes and failures

An ELISA coproantigen detection assay for Fasciola spp is commercially avalaible which can detect adult worm infections but is less reliable for immature pre-patent stages. There has been less progress in coproantigen detection in nematodes of livestock although there are commercially available coproantigen detection tests for companion
animal nematodes such as Toxocara, Trichuris and hookworms. These have somewhat greater sensitivity that egg detection by fecal flotations and are more scalable.