Phylogeny[2] analysis of the 18S rDNA and gGADPH loci that T. Irwini is genetically closest to Trypanosoma bennetti, which is an avian trypanosome.

Further comparison of the 18S rDNA sequences against the data available in the Genbank shows that T. irwini can be grouped with Trypanosoma minasense, which is a trypanosome of neotropical primates collected from Australian marsupials.

Blood smears show Trypanosoma irwini parasites with physical characteristics resembling the trypomastigote stage of other well-known trypanosomatids.

A post-mortem examination revealed osteochondromas in the ribs, lymphoid atrophy, extensive periacinar necrosis of the liver, interstitial nephritis, extramedullary hematopoiesis of the spleen, and other problems.

While not all of these clinical and pathological findings are consistent with symptoms and signs of trypanosomiasis, those that suggest extravascular hemolysis and generalized immune reaction are.