Trypanosoma irwini n. sp (Sarcomastigophora: Trypanosomatidae) from the koala (Phascolarctos cinereus)
L. M. MCINNES 1*, A. GILLETT 2, U. M. RYAN 1, J. AUSTEN 1, R. S. F. CAMPBELL3, J. HANGER 2 and S. A. REID 1
1 Division of Health Sciences, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Perth 6150, Western Australia
2 The Australian Wildlife Hospital, Beerwah, Queensland, Australia
3 School of Veterinary Science, James Cook University, Townsville, Queensland 4811, Australia
The morphology and genetic characterization of a new species of trypanosome infecting koalas (Phascolarctos cinereus) are described. Morphological analysis of bloodstream forms and phylogenetic analysis at the 18S rDNA and gGAPDH loci demonstrated this trypanosome species to be genetically distinct and most similar to Trypanosoma bennetti, an avian trypanosome with a genetic distance of 0.9% at the 18S rDNA and 10.7% at the gGAPDH locus. The trypanosome was detected by 18S rDNA PCR in the blood samples of 26 out of 68 (38.2%) koalas studied. The aetiological role of trypanosomes in koala disease is currently poorly deﬁned, although infection with these parasites has been associated with severe clinical signs in a number of koalas. Based on biological and genetic characterization data, this trypanosome species infecting koalas is proposed to be a new species Trypanosome irwini n. sp.