Original Articles

Trypanosomes in a declining species of threatened Australian marsupial, the brush-tailed bettong Bettongia penicillata (Marsupialia: Potoroidae)

A. SMITH^a1 c1, P. CLARK^a1, S. AVERIS^a1, A. J. LYMBERY^a1, A. F. WAYNE^a2, K. D. MORRIS^a3 and R. C. A. THOMPSON^a1

^a1 WHO Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and the State Agricultural Biotechnology Centre, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Western Australia 6150, Australia

^a2 Science Division, Department of Environment and Conservation, Manjimup, WA 6258, Australia

^a3 Science Division, Department of Environment and Conservation, Wildlife Place, Woodvale WA 6026, Australia

SUMMARY

The brush-tailed bettong (Bettongia penicillata), or woylie, is a medium-sized macropod marsupial that has undergone a rapid and substantial decline throughout its home range in the Upper Warren region of Western Australia over a period of approximately 5 years. As part of an investigation into possible causes of the decline a morphologically distinct Trypanosoma sp. was discovered by light microscopy in the declining population but was absent in a stable population within the Karakamia Wildlife Sanctuary. Further investigations employing molecular methods targeting variations in the 18s rRNA gene determined that the trypanosome was novel and was also present within the Karakamia population albeit at a much lower overall prevalence and individual parasitaemia levels. Phylogenetic analysis suggests the novel Trypanosoma sp. to be closely related to other trypanosomes isolated from native Australian wildlife species. Although it appears unlikely that the parasite is solely responsible for the decline in woylie population size, it may (singularly or in conjunction with other infectious agents) predispose woylies to increased mortality.

(Received April 28 2008)

(Revised May 28 2008)

(Accepted June 16 2008)

(Online publication August 28 2008)

Key Words:

• trypanosome;
• Bettongia penicillata;
• woylie;
• population decline;
• characterization;
• wildlife;
• parasite

Correspondence:

^c1 Corresponding author: WHO Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and the State Agricultural Biotechnology Centre, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Western Australia 6150, Australia. Tel: +08 9965 0908. E-mail: andrew.smith@murdoch.edu.au