Novel trypanosome Trypanosoma gilletti sp. (Euglenozoa: Trypanosomatidae) and the extension of the host range of Trypanosoma copemani to include the koala (Phascolarctos cinereus)

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 (similar to 2%) blood samples and in 2/29 (similar to 7%) spleen tissue samples from koalas whilst T. irwini was detected in 72/139 (similar to 52%) blood samples and T. copemani in 4/139 (similar to 3%) blood samples from koalas. In addition, naturally occurring mixed infections were noted in 2/139 (similar to 1.5%) of the koalas tested.