A repeatable and quantitative DNA metabarcoding assay to characterize mixed strongyle infections in horses

Jocelyn Poissant, Stefan Gavriliuc, Jennifer Bellaw, Elizabeth M. Redman, Russell W. Avramenko, David Robinson, Matthew L. Workentine, Todd K. Shury, Emily J. Jenkins, Philip D. McLoughlin, Martin K. Nielsen, John S. Gilleard

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Horses are ubiquitously infected by a diversity of gastro-intestinal parasitic helminths. Of particular importance are nematodes of the family Strongylidae, which can significantly impact horse health and performance. However, knowledge about equine strongyles remains limited due to our inability to identify most species non-invasively using traditional morphological techniques. We developed a new internal transcribed spacer 2 (ITS2) DNA metabarcoding ‘nemabiome’ assay to characterise mixed strongyle infections in horses and assessed its performance by applying it to pools of infective larvae from fecal samples from an experimental herd in Kentucky, USA and two feral horse populations from Sable Island and Alberta, Canada. In addition to reporting the detection of 33 different species with high confidence, we illustrate the assay's repeatability by comparing results generated from aliquots from the same fecal samples and from individual horses sampled repeatedly over multiple days or months. We also validate the quantitative potential of the assay by demonstrating that the proportion of amplicon reads assigned to different species scales linearly with the number of larvae present. This new tool significantly improves equine strongyle diagnostics, presenting opportunities for research on species-specific anthelmintic resistance and the causes and consequences of variation in mixed infections.

Original languageEnglish
Pages (from-to)183-192
Number of pages10
JournalInternational Journal for Parasitology
Issue number2-3
StatePublished - Feb 2021

Bibliographical note

Publisher Copyright:
© 2020 Australian Society for Parasitology


  • Cyathostomin
  • Diagnostic
  • Host-parasite interaction
  • Nemabiome
  • Nematode
  • Parasitology

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases


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