Characterizing parasitic nematode faunas in faeces and soil using DNA metabarcoding

Area of Science:

• Veterinary Parasitology
• Molecular Ecology
• Wildlife Health

Background:

• Gastrointestinal parasitic nematodes significantly impact wild vertebrate populations, affecting health and survival.
• Traditional monitoring relies on morphological identification of parasite stages, often requiring dead animals for species-level accuracy.
• DNA metabarcoding offers a high-throughput, cost-effective alternative for biodiversity monitoring, applicable to parasite communities.

Purpose of the Study:

• To evaluate DNA metabarcoding for non-invasive monitoring of gastrointestinal parasitic nematodes in wild reindeer.
• To compare DNA metabarcoding with traditional morphological methods for characterizing nematode communities.
• To assess the utility of soil samples for detecting free-living parasite stages.

Main Methods:

• Collected faeces, intestines, and soil samples from a wild reindeer population.
• Characterized nematode fauna using traditional morphological techniques (flotation, sedimentation).
• Employed DNA metabarcoding on bulk and pre-treated (sedimentation/flotation) samples.

Main Results:

• DNA metabarcoding and morphological methods yielded congruent nematode fauna profiles.
• Metabarcoding provided higher taxonomic resolution than morphological identification in faeces and soil.
• Pre-treatments reduced non-target DNA but did not enhance species detection rates in faeces or soil.

Conclusions:

• DNA metabarcoding of faeces is a non-invasive, efficient method for assessing parasitic nematode populations.
• This molecular approach achieves taxonomic resolution comparable to invasive methods.
• Detecting nematodes in soil highlights the method's potential for mapping parasite distribution and free-living stages.