qPCR-based environmental monitoring of the whirling disease-causing parasite Myxobolus cerebralis and phylogenetic analysis of the tubificid hosts in Alberta, Canada

Myxobolus cerebralis is the causative agent of whirling disease in salmonid fishes. In 2016, this invasive parasite was detected Alberta, Canada, for first time, initiating a comprehensive 3 yr monitoring program to assess where had spread within province. As part program, qPCR-based test developed facilitate detection environmental stages M. and from oligochaete host, Tubifex tubifex. During ~1500 samples were collected tested over yr. Fish same watersheds 2 as official provincial effort. Substrate testing identified sites positive 6 that been confirmed by fish-based novel detections not previously. Testing individually isolated each sample site used further confirm presence cerebralis. DNA barcoding cytochrome oxidase I (cox1) gene 567 specimens different yielded 158 unique sequences belonging 21 genera 37 putative species. Phylogenetic analyses assigned genus predicted 5 species arising assessment. Based on our results, we propose worm can be valuable complement gold-standard fish will especially useful areas collection challenging or prohibitive because accessibility vulnerability populations.