Doctoral Thesis
The molecular systematics of Giardia duodenalis
Doctor of Philosophy (PhD), Murdoch University
2024
Abstract
Giardia is a ubiquitous intestinal parasite of vertebrates. Characterisation and differentiation of separate Giardia species from different hosts has been hampered by morphological homogeneity and low-resolution sequencing loci. Validation of PCR methods, and characterisation of available GenBank reference sequences, has been a work in progress alongside the advancing knowledge of the broad genetic and host range of Giardia species.
The current research project focused on the species complex of Giardia duodenalis found in humans and numerous domestic and wild animals. The project commenced after sequence surveys identified limitations of the currently used typing loci, and progressed with trials to improve PCR techniques and concluded in validation of the gdh and tpi loci for preliminary sub-Assemblage A and sub-Assemblage B analyses respectively. Results demonstrated support for description of separate species within the species complex and literature reviews highlighted historic nomenclatural acts pertinent to the separate species identified based on mutual host associations. Therefore the Assemblages of the Giardia duodenalis species complex were synonymised to existing historical names. Zoonotic sub-Assemblage AI was synonymised to Giardia duodenalis (Davaine, 1875), human associated sub-Assemblage AII to Giardia intestinalis (Lambl, 1859), zoonotic Assemblage B to Giardia enterica (Grassi, 1881), dog associated Assemblage C to Giardia canis Hegner, 1922, artiodactyl associated Assemblage E to Giardia bovis Fantham, 1921, feline associated Assemblage F to Giardia cati Deschiens, 1925 and rodent associated Assemblage G to Giardia simoni Lavier, 1924. Canid associated Assemblage D, without a previous nomenclatural act was named Giardia lupus Wielinga et al., 2023 and seal associated Assemblage H was proposed for discussion as “pinnipedis” and wild ruminant Assemblage AIII as “cervus”.
Details
- Title
- The molecular systematics of Giardia duodenalis
- Authors/Creators
- Caroline Wielinga
- Contributors
- Una Ryan (Supervisor) - Murdoch University, Centre for Biosecurity and One HealthAndrew Thompson (Supervisor)Paul Monis (Supervisor) - South Australian Water Corporation
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005692866007891
- Murdoch Affiliation
- Centre for Biosecurity and One Health
- Resource Type
- Doctoral Thesis
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