Acanthocephalan parasites collected from Austrian fishes: molecular barcoding and pathological observations

Area of Science:

• Parasitology
• Ichthyology
• Molecular Biology

Background:

• Acanthocephalan parasites are common fish endoparasites.
• Understanding their distribution and impact is crucial for fish health management.
• Molecular barcoding enhances parasite identification and genetic diversity assessment.

Purpose of the Study:

• To investigate the diversity and distribution of acanthocephalans in wild fish populations in Austria.
• To assess the impact of acanthocephalan infections on fish condition factor and pathology.
• To generate molecular data for acanthocephalan species identification and genetic characterization.

Main Methods:

• Fish (barbel, chub, rainbow trout, brown trout) were sampled from 12 localities in Austria.
• Parasite intensity, condition factor, and pathological lesions were recorded.
• DNA barcoding of acanthocephalans using the mitochondrial cytochrome c oxidase subunit I (COI) gene was performed.
• Brown trout were tested for Tetracapsolioides bryosalmonae via PCR.

Main Results:

• 113 acanthocephalans were identified, with 77 COI sequences generated.
• Echinorhynchus truttae (56 sequences, 3 genotypes) and Pomphorhynchus tereticollis (11 sequences, 9 genotypes) were dominant.
• New genotypes for these species were reported, alongside Acanthocephalus sp. and Neoechinorhynchida.
• Acanthocephalan infection did not significantly impact the condition factor of brown trout.
• Pomphorhynchus tereticollis infections resulted in more severe pathological changes than Echinorhynchus truttae.

Conclusions:

• This study provides novel insights into acanthocephalan species distribution and genetic diversity in Austrian freshwater fish.
• Pomphorhynchus tereticollis was confirmed in European chub and for the first time in brown and rainbow trout in Austria.
• While not affecting overall condition, specific acanthocephalans like P. tereticollis can cause significant digestive tract pathology.