Novel trypanosome Trypanosoma gilletti sp. (Euglenozoa: Trypanosomatidae) and the extension of the host range ofTrypanosoma copemani to include the koala (Phascolarctos cinereus)
L. M. MCINNES1*, J. HANGER2, G. SIMMONS3, S. A. REID1 and U. M. RYAN1
1Division of Health Sciences, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Perth, WA 6150, Australia
2The Australian Wildlife Hospital, Beerwah, Qld 4519 and
3School of Veterinary Science, University of Queensland, St Lucia, Qld 4072, Australia
Trypanosoma irwini was previously described from koalas and we now report the finding of a second novel species, T. gilletti, as well as the extension of the host range of Trypanosoma copemani to include koalas. Phylogenetic analysis at the 18S rDNA and gGAPDH loci demonstrated that T. gilletti was genetically distinct with a genetic distance (± S.E.) at the 18S rDNA locus of 2·7±0·5% from T. copemani (wombat). At the gGAPDH locus, the genetic distance (± S.E.) of T. gilletti was 8·7±1·1% from T. copemani (wombat). Trypanosoma gilletti was detected using a nested trypanosome 18S rDNA PCR in 3/139 (~2%) blood samples and in 2/29 (~7%) spleen tissue samples from koalas whilst T. irwini was detected in 72/139 (~52%) blood samples and T. copemani in 4/139 (~3%) blood samples from koalas. In addition, naturally occurring mixed infections were noted in 2/139 (~1·5%) of the koalas tested.