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The koala (Phascolarctos cinereus) is an iconic Australian marsupial that is under threat of extinction across two thirds of its range, with populations recently listed as ‘endangered’ in Queensland (QLD), New South Wales (NSW) and the Australian Capital Territory (ACT). Many risk factors have been implicated in the koala population decline, including habitat loss, vehicle collisions, dog attack and infectious diseases such as chlamydiosis and koala immune deficiency syndrome caused by koala retrovirus (KoRV). Trypanosomes are blood-borne protozoan parasites that can infect all classes of mammals and are known to cause serious disease in humans and domestic livestock worldwide. Recent studies have identified numerous Trypanosoma species in a range of Australian marsupials, including the koala which is known to harbour up to six species in either single or mixed infections: Trypanosoma irwini, Trypanosoma gilletti, Trypanosoma copemani, Trypanosoma vegrandis, Trypanosoma noyesi and Trypanosoma sp. AB-2017. Importantly, preliminary data from analyses of hospitalised koalas in QLD suggest that trypanosome infections (alone or with concurrent diseases) may adversely affect koala health and survival. Whilst a large number of studies have been conducted on chlamydia and KoRV, there is still a paucity of research investigating the prevalence, diversity and clinical impact of trypanosomes in koalas. In particular, there is a dearth of research comprising random, representative samples from various wild koala populations across Australia, including more stable populations from South Australia (SA). This descriptive cross-sectional study utilised nested PCR, targeting partial fragments of the nuclear 18S ribosomal RNA (18S rRNA) gene, to screen blood samples from wild-caught koalas for the presence of trypanosomes. Samples were randomly collected from koalas belonging to two distinct wild populations; Moreton Bay, Queensland (QLD) (n= 72) and Mount Lofty, South Australia (SA)

Ticks pose a major threat to the health and wellbeing of humans, domesticated animals and wildlife. Recently, a bacterial community study (16S rRNA) on the stump-tailed lizard tick, Amblyomma albolimbatum, removed from bobtails, Tiliqua rugosa, in Western Australia (WA), revealed the presence of Coxiella, Francisella and Rickettsia DNA sequences. However, resolution to species level could not be achieved due to the short sequences generated through next generation sequencing. In addition, oocytes proposed to be Hemolivia sp. have been identified within the gut epithelium of A. albolimbatum; however molecular data confirming the species is lacking. Here we present for the first time, molecular data supporting the presence of Coxiella burnetii, Francisella sp. nov., Rickettsia spp. and Hemolivia mariae within A. albolimbatum in WA. Three hundred and six ticks, morphologically identified as A. albolimbatum, were removed from 88 T. rugosa lizards at the Kanyana Wildlife Rehabilitation Centre, Perth, WA from 2013 to 2015. A subset of 142 ticks were subjected to genomic DNA extraction and screened for Coxiella, Francisella, Rickettsia using genus-specific assays and haemoparasites using a nested 18S rRNA assay followed by Sanger sequencing. Coxiella burnetii was found in a single A. albolimbatum based on 16S and GroEL genes. Coxiella burnetii is the causative agent of Q fever and coxiellosis in people and animals, respectively, and therefore, its presence is of major concern. Secondly, a Francisella sp. nov. based on a concatenated alignment of 4,230 bp (16S, tpiA, prfB, rpoA, dnaA) was generated with a 3% genetic distance to F. persica, a known soft tick endosymbiont. Interestingly, there was evidence of three Rickettsia spp. which warrants further investigation as two were closely related to the Spotted Fever Rickettsia spp. group. Lastly, two samples had a 100% genetic identity to H. mariae at the 18S gene, which is consistent with the previous report of Hemolivia with

Trypanosomes are blood-borne parasites that can cause severe disease in both humans and animals, resulting in very large economic losses worldwide. In contrast to the wealth of information on pathogenic species such as Trypanosoma cruzi and Trypanosoma brucei, little is known of the pathogenicity, prevalence and life-cycles of trypanosomes in native Australian mammals. The aim of this thesis was to characterise trypanosomes and other protozoans from the critically endangered Gilbert’s potoroo (Potorous gilbertii) and the quokka (Setonix brachyurus) from Western Australia using morphological and molecular analysis. A novel Trypanosoma species, Trypanosoma copemani was identified in Gilbert’s potoroos and quokkas using molecular and morphological analysis. Further molecular characterisation of T. copemani in quokkas at both the 18S rRNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) loci identified multiple T. copemani genotypes revealing that the parasite is genetically variable. Given the phylogenetic grouping of T. copemani as a stercorarian (requiring faecal transmission by vector), the fact that ticks are common ectoparasites of Gilbert’s potoroos and quokkas and the previous identification of trypanosomes in ticks, ticks were examined as potential vectors of T. copemani. Motile trypanosomes were detected in both the haemolymph and midgut sections of Ixodes australiensis ticks removed from quokkas and Gilbert’s potoroos and stained trypanosomes were detected within a faecal smear. Morphologically, the tick trypanosomes resembled in vitro forms of T. copemani, representing epimastigotes and slender trypomastigote stages, with dividing stages detected within the midgut region. Molecular analysis of the tick isolates, showed 100% sequence identity to T. copemani at the 18S rRNA locus, suggesting that the tick is a putative vector for T. copemani. Investigation of the life-cycle stages of native Australian trypanosomes using microscopy and in vitro culture of b

During July/August 2010, 28 Christmas Island flying foxes (Pteropus melanotus natalis) were captured and anesthetized for examination, sample collection, and release to determine the potential role of disease in recent population declines. Measurements and samples were taken for morphologic, hematologic, biochemical, and parasitologic analysis. These are the first blood reference ranges reported for this species. These data are being used to inform investigations into conservation status and population management strategies for the Christmas Island flying fox.