Assessing whole-host homogenisation as a new tool for parasite detection and identification

Despite their importance in ecosystem functioning, parasites remain the most neglected components of biodiversity monitoring. This neglect is partly due to the methodological challenges associated with their detection and identification. Current traditional morphological and molecular approaches are time-consuming, labour-intensive, and require specialised expertise. Here, we explore a novel approach of deriving parasite information through whole-host homogenisation followed by DNA-based identification of its parasite biota. Our goal was to validate whether the approach is feasible and if it could become a complementary method for studying parasites, providing a time-efficient solution allowing for a holistic parasite scan with limited taxonomic expertise. To test the method's efficiency, we analysed five specimens of European eel as model hosts. Their parasites were identified morphologically, and then all the parasites and the entire host tissue were homogenised together using a commercial blender. Molecular identification of the morphologically detected parasites was conducted using DNA barcoding with parasite-specific primers. Following homogenisation and DNA-based identification, we successfully detected all parasite taxa identified during morphological analyses, even including instances where they had not been detected morphologically. A notable exception were acanthocephalans, which showed low levels of molecular detection. Despite certain limitations, the detection of parasites directly from the whole-host homogenate shows high potential for efficient and accurate parasite detection, in some cases even surpassing morphological identification. The further development of the method, particularly through exploration of DNA metabarcoding, could improve the reliability of parasite assessments and facilitate parasite detection, which could aid in proper parasite recognition.