DNA-Based Environmental Monitoring for the Invasive Myxozoan Parasite, Myxobolus cerebralis, in Alberta, Canada

• Author / Creator

  Barry, Danielle E.

• Whirling disease is a disease of fish caused by an invasive myxosporean parasite, Myxobolus cerebralis. It was first detected in Canada in Johnson Lake in Banff National Park, Alberta, in August 2016, and little is known about the transmission of this parasite in Canada. Current testing focuses on the detection of M. cerebralis in fish tissues, requiring lethal testing of both infected and non-infected fish. However, the parasite has a definitive host, the oligochaete worm Tubifex tubifex and two environmental stages found in water and sediment that create other avenues for detection. We propose that using the parasite stages found in water and sediment and the alternate worm host, Tubifex tubifex, are a reasonable complement to fish sampling and will be especially useful for sampling in areas where fish collection is challenging or prohibitive due to vulnerability of the fish populations. In addition, T. tubifex susceptibility to M. cerebralis is not consistent across the species, with experiments showing some are refractory. Characterization of these worm populations will help target future monitoring and control programs based on the presence or absence of susceptible T. tubifex.
  This project utilized ~5000 samples collected over two years. These include sediment samples, invertebrate worm samples and water samples from stocked ponds. DNA was extracted from these samples using different methods tailored to the sample type and tested in a newly developed qPCR assay targeting the 18S gene of M. cerebralis. Additionally, worm samples were barcoded by targeting the cox1 gene to determine species, since as previous tests for M. cerebralis compatibility proved unreliable identification by morphology is unreliable.
  I detected M. cerebralis with the new qPCR test at 18 different sites including two novel detections in previously negative water sheds, Athabasca and Peace River, where fish testing had all returned negative or was unable to be done. The worm host barcoding showed 37 different species belonging to 21 genera. The genus Tubifex was divided into five different taxonomic groups, with a currently unknown variation in M. cerebralis compatibility. This work is an important early step to understanding the biology and providing alternatives for detection of this invasive parasite in Alberta to best inform management decisions in order to protect our natural resources.

• Subjects / Keywords

  • environmental monitoring
  • molecular parasitology
  • qPCR testing
  • myxobolus cerebralis
  • whirling disease

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-9h48-tk93

• License

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