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Rebecca Vaughan BSc BVMS

A Doctor of Philosophy Thesis

Health and disease status of Australia’s most critically endangered mammal, the Gilbert’s potoroo (Potorous gilbertii)

Supervisors

  • Dr Kris Warren BSc BVMS (Hons) PhD, Murdoch University
  • Dr Cree Monaghan BSc BVMS MSc, Perth Zoo
  • Dr Stan Fenwick BVMS MSc PhD, Murdoch University

Dr Vaughan’s research examined the health and disease status of the Gilbert’s potoroo (Potorous gilbertii), Australia’s most critically endangered mammal (IUCN 2006).  This small marsupial, which was presumed extinct until 1994, is endemic only to the Two Peoples Bay Nature Reserve in the south-west of Western Australia, and at the time of this study had an estimated population of only 40 individuals. Dr Vaughan and collaborators undertook long-term health monitoring of both the wild population and a much smaller captive population, to assess the prevalence of specific diseases and to correlate the effects of indentified diseases on population dynamics, including reproductive success and survivorship.  Findings from the research have led to the formation of population health management procedures to facilitate the conservation of the last remaining Gilbert’s potoroos.

Specific diseases which were extensively studied by Dr Vaughan included Cryptococcus,ectoparasitism, endoparasitism, haemoparasitism, Toxoplasma, and a novel Treponema organism.  The work included a detailed assessment of the clinical significance of each of these diseases for the Gilbert’s potoroo, and produced key recommendations for management strategies to minimise the impact of these diseases on both wild and captive populations.

In particular, the research included the molecular characterisation of the novel Treponema organism, which presents clinically with tenacious green discharge and an associated balanoposthitis in male potoroos.  Epidemiological studies demonstrated that this agent could potentially have negative effects on reproductive function, and a penicillin-based treatment regime was trialled in the analogous long-nosed potoroo (Potorous tridactylus).  The success of these trials in long-nosed potoroos has led to a recommendation for this treatment regime being trialled in the critically endangered Gilbert’s potoroo, which could be undertaken if further epidemiological studies indicate that the infection is adversely affecting potoroo health or reproductive success.

Another first from Dr Vaughan’s research includes the tabulation of standard haematological and urinalysis findings, to produce reference ranges for this species.  The thesis also describes and discusses the study’s parasitological findings, as well as a treatment regime for Cryptococcus in the analogous long-nosed potoroo.

Dr Vaughan’s research addressed a wide range of key health issues for the Gilbert’s potoroo, which are now highlighted in the Recovery Plan for the Gilbert’s potoroo; a document which encompasses multiple disciplines and expertise to support the recovery of this critically endangered marsupial in its current environment.  Importantly, Dr Vaughan’s thesis presents a detailed ongoing health monitoring and treatment protocol for future widespread translocation programmes, and provides a working example of the importance of in-situ health monitoring of threatened wildlife species within their specific ecological contexts.

This thesis is available in Murdoch University's Digital Thesis collection - http://wwwlib.murdoch.edu.au/adt/

Publications

  • Vaughan RJ, Buller N, Friend AJ, Robertson I, Monaghan CL, Fenwick S and Warren K, Balanoposthitis, dysparenuria and Treponema in Australia’s most critically endangered mammal, the Gilbert’s Potoroo (Potorous gilbertii), submitted EID (2010)
  • Vaughan RJ, Warren KS, Mills J, Palmer C, Fenwick S, Monaghan CL, Friend JA (2009), Haematological and serum biochemical reference values and cohort analysis in the Gilbert’s potoroo (Potorous gilbertii), Journal of Zoo and Wildlife Medicine,  40(2): 276–288.
  • Vaughan RJ, Vitali SD, Eden PA, Payne KL, Warren KS, Forshaw D, Friend JA, Horwitz AM, Main C, & Krockenberger MB. (2007)  Cryptococcosis in Gilbert’s and long-nosed potoroo.  Journal of Zoo and Wildlife Medicine, 38(4), 567-573.

Conferences

  • 2007: Preliminary findings in the investigation of the significance of a Treponema-like organism isolated from Australia’s most critically endangered mammal – the Gilbert’s potoroo (Potorous gilbertii), R.J. Vaughan, K. Warren, T.F. Friend, N. Buller, C.M. Monaghan, S. Fenwick and D. Forshaw, West Australian Department of Fisheries, Agriculture and Food Conference, Hilary’s Western Australia, 11-12 June 2007 (presented by Dr R Vaughan).
  • 2007: Epidemiological aspects of health management of the Gilbert’s potoroo (Potorous gilbertii), RJ. Vaughan, K. Warren, TF. Friend, N. Buller, CM. Monaghan, S. Fenwick and D. Forshaw, Wildlife Disease Association (Australasian section) National Conference, Dryandra, Western Australia, 22-28 September 2007 (presented by Dr R Vaughan).
  • 2007: Determining the significance of a Treponema-like organism isolated from Australia’s most critically endangered mammal, the Gilbert’s potoroo (Potorous gilbertii), RJ. Vaughan, K. Warren, TF. Friend, N. Buller, CM. Monaghan, S. Fenwick, and D. Forshaw,  American Association of Zoo Veterinarians Conference, Knoxsville Tennessee 20-26 October 2007 (presented by Dr R Vaughan).
  • 2006: Epidemiological aspects of health management of Gilbert’s potoroo (Potorous gilbertii) – Australia’s most endangered mammal, KS Warren, R Vaughan, T Friend, N Buller, C Monaghan, S Fenwick and I Robertson, Proceedings American Association of Zoo Veterinarians Conference, 20-24 September, Tampa, Florida (presented by Dr K Warren).
  • 2005: Quantitative detection of chlamydial infections in animals using a real time polymerase chain reaction assay based on a conserved region of the 16S rRNA gene, B Markey, C Wan, R Vaughan, L Woolford, M Bennett, K Warren, A O’Hara, R Swan, T Friend, P de Tores and P Timms, 3rd Workshop of COST Action 855, Diagnosis and Pathogenesis of Animal Chlamydioses, Siena, September 22-23, 2005 (presented by Dr B Markey).
  • 2005:    Cryptococcal infections in captive Gilbert’s (Potorous gilbertii) and Long-nosed (Potorous tridactylus) potoroos (2005) RJ Vaughan, SD Vitali, PA Eden, K Payne, KS Warren, A Horwitz, JA Friend, M Krockenberger, Wildlife Health in a Shrinking World – Ecology, Management and Conservation, Wildlife Disease Association Conference, 28 June-2 July 2005, Cairns Australia (presented by Dr R Vaughan).

Collaborators (positions held at Jan 2010)

  • Dr Tony Friend, Principal Research Scientist, Department of Environment and Conservation.
  • Dr Nicky Buller, Animal Health Laboratories (AHL), Department of Agriculture WA, Senior Microbiologist.
  • Dr Jenny Mills, Senior Lecturer - Clinical Pathology, School of Veterinary and Biomedical Sciences, Murdoch University.
  • Professor Ian Robertson, Veterinary Epidemiology, School of Veterinary and Biomedical Sciences, Murdoch University.
  • Associate Professor Peter Irwin, Small Animal Medicine, School of Veterinary and Biomedical Sciences, Murdoch University
  • Professor Elizabeth Deane, Pro Vice-Chancellor (students), Australian National University
  • Dr Mark Krockenberger, Senior Lecturer in Veterinary Pathology, Faculty of Veterinary Science, University of Sydney
  • Professor Peter Timms, Professor of Microbiology, School of Life Sciences, Queensland University of Technology
  • Dr David Forshaw, Pathologist and Senior Veterinary Officer, WA Department of Agriculture

Acknowledgements

This research was undertaken with financial support provided by Perth Zoo, Murdoch University Veterinary Trust and School of Veterinary and Biomedical Sciences Murdoch University.

Photos provided by Rebecca Vaughan

Department of Environment and ConservationPerth Zoo