Search

Conventional nested PCR and Sanger sequencing methods are currently the gold standards for detecting trypanosomes in wildlife. However, these techniques are time-consuming and can often overlook mixed infections. True trypanosome prevalence can thus be underrepresented. Here, we designed an 18S rDNA-based real-time quantitative PCR (qPCR) assay coupled with High-Resolution Melting Analysis (HRMA) to detect and discriminate three Trypanosoma species (T. copemani, T. noyesi, and T. vegrandis) commonly infecting Australian marsupials. A total of 68 genetically characterised samples from blood and tissue were used to validate the High-Resolution Melting - Real Time Quantitative Polymerase Chain Reaction (HRM-qPCR) assay. A further 87 marsupial samples consisting of blood, tissue and in vitro cultures derived from wildlife blood samples, were screened for the first time using this assay, and species identity confirmed using conventional PCR and Sanger sequencing. All three Trypanosoma species were successfully detected in pure cultures using the HRM-qPCR assay, and in samples containing mixed trypanosome infections. Of the 87 marsupial samples screened using the HRM-qPCR assay, 93.1% were positive for trypanosomes, and 8.0% contained more than one trypanosome species. In addition to the three targeted Trypanosoma species, this assay was also able to detect and identify other native and exotic trypanosomes. The turnaround time for this assay, from sample preparation to obtaining results, was less than 2 h, with a detection limit of 10 copies of the amplicon in a reaction for each of the targeted trypanosome species. This more rapid and sensitive diagnostic tool provides a high throughput platform for the detection, identification and quantification of trypanosome infections. It will also improve understanding of host diversity and parasite relationships and facilitate conservation management decisions., Graphical abstract Image 1

Fauna translocations play an integral role in the management of threatened wildlife, though we are limited by our understanding of how the host-parasite community changes during translocation. During this longitudinal field-based study, we monitored gastrointestinal, blood-borne and ectoparasite taxa infecting woylies (Bettongia penicillata) for up to 12 months following two fauna translocations to supplement existing wild woylie populations in three different sites (Dryandra, Walcott and Warrup East) within the south-west of Western Australia. We aimed to (a) identify changes in parasite community structure of both translocated and resident woylies following translocation; and (b) evaluate the efficacy of ivermectin treatment in translocated hosts. Destination site and time since translocation had the strongest effects on parasite prevalence and mean faecal egg counts following translocation. Ivermectin treatment did not significantly reduce parasite prevalence or mean faecal egg counts in treated hosts. Prior to translocation, parasite community composition differed significantly between woylies selected for translocation and resident woylies within each release site. Following translocation, the parasite communities of translocated and resident hosts converged to become more similar over time, with loss of parasite taxa and novel host-parasite associations emerging. This is the first study to examine changes to the broader parasite community in translocated and resident animals following translocation. The dominant site-specific response of parasites following translocation reinforces the importance of incorporating parasite studies to enhance our fundamental understanding of perturbations in host-parasite systems during translocation, in particular the site-level drivers of parasite dynamics., Graphical abstract Image 1, Highlights • Perturbations to host-parasite systems during translocation are poorly understood. • Parasite dynamics were strongly impacted by site and time since translocation. • The parasite communities of translocated and resident hosts converged over time. • Ivermectin treatment had no significant impact on target parasites. • Translocation protocols should consider the intrinsic biodiversity value of parasites.

Advances in sequencing technologies have revealed the complex and diverse microbial communities present in ticks (Ixodida). As obligate blood-feeding arthropods, ticks are responsible for a number of infectious diseases that can affect humans, livestock, domestic animals and wildlife. While cases of human tick-borne diseases continue to increase in the northern hemisphere, there has been relatively little recognition of zoonotic tick-borne pathogens in Australia. Over the past 5 years, studies using high-throughput sequencing technologies have shown that Australian ticks harbour unique and diverse bacterial communities. In the present study, free-ranging wildlife (n=203), representing ten mammal species, were sampled from urban and peri-urban areas in New South Wales (NSW), Queensland (QLD) and Western Australia (WA). Bacterial metabarcoding targeting the 16S rRNA locus was used to characterize the microbiomes of three sample types collected from wildlife: blood, ticks and tissue samples. Further sequence information was obtained for selected taxa of interest. Six tick species were identified from wildlife: Amblyomma triguttatum, Ixodes antechini, Ixodes australiensis, Ixodes holocyclus, Ixodes tasmani and Ixodes trichosuri. Bacterial 16S rRNA metabarcoding was performed on 536 samples and 65 controls, generating over 100 million sequences. Alpha diversity was significantly different between the three sample types, with tissue samples displaying the highest alpha diversity (P Proteobacteria was the most abundant taxon identified across all sample types (37.3 %). Beta diversity analysis and ordination revealed little overlap between the three sample types (P Anaplasmataceae , Bartonella , Borrelia , Coxiellaceae , Francisella , Midichloria , Mycoplasma and Rickettsia . Anaplasmataceae bacteria were detected in 17.7% (95/536) of samples and included Anaplasma , Ehrlichia and Neoehrlichia species. In samples from NSW, ‘Ca. Neoehrlichia australis’, ‘Ca. Neoehrlichia arcana’, Neoehrlichia sp. and Ehrlichia sp. were identified. A putative novel Ehrlichia sp. was identified from WA and Anaplasma platys was identified from QLD. Nine rodent tissue samples were positive for a novel Borrelia sp. that formed a phylogenetically distinct clade separate from the Lyme Borrelia and relapsing fever groups. This novel clade included recently identified rodent-associated Borrelia genotypes, which were described from Spain and North America. Bartonella was identified in 12.9% (69/536) of samples. Over half of these positive samples were obtained from black rats (Rattus rattus), and the dominant bacterial species identified were Bartonella coopersplainsensis and Bartonella queenslandensis . The results from the present study show the value of using unbiased high-throughput sequencing applied to samples collected from wildlife. In addition to understanding the sylvatic cycle of known vector-associated pathogens, surveillance work is important to ensure preparedness for potential zoonotic spillover events.

Faecal samples (n = 1,093) collected from the woylie Bettongia penicillata Gray, in south-western Australia were examined for the presence of coccidian parasites. Eimeria sp. oocysts were detected in 15.2% of samples. Faecal samples obtained from the eastern bettong Bettongia gaimardi (Desmarest) (n = 4) and long-nosed potoroo Potorous tridactylus (Kerr) (n = 12) in Tasmania, were also screened for the presence of Eimeria spp. (prevalence 50% and 41.7%, respectively). Morphological and genetic comparison with other known species of Eimeria indicates that the material identified in woylies is novel. This study aimed to (i) morphologically describe and genetically characterise Eimeria woyliei n. sp. found in woylies; and (ii) genetically characterise Eimeria gaimardi Barker, O’Callaghan & Beveridge, 1988, Eimeria potoroi Barker, O’Callaghan & Beveridge, 1988, and Eimeria mundayi Barker, O’Callaghan & Beveridge, 1988, from other potoroid marsupials. Molecular phylogenetic analyses conducted at the 18S rDNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) loci revealed that E. woyliei n. sp. was most closely related to Eimeria setonicis Barker, O’Callaghan & Beveridge, 1988, at the 18S rDNA locus, and Eimeria trichosuri O’Callaghan & O’Donoghue, 2001, at the cox1 locus. Eimeria woyliei n. sp. is the sixth species of Eimeria to be formally described from potoroid marsupials.

During monitoring of critically endangered woylie (Bettongia penicillata) populations within the south-west of Western Australia, an adult female woylie was euthanased after being found in extremely poor body condition with diffuse alopecia, debilitating skin lesions and severe ectoparasite infestation. Trypanosoma copemani G2 and Sarcocystis sp. were detected molecularly within tissue samples collected post-mortem. Potorostrongylus woyliei and Paraustrostrongylus sp. nematodes were present within the stomach and small intestine, respectively. Blood collected ante-mortem revealed the presence of moderate hypomagnesaemia, mild hypokalaemia, mild hyperglobulinaemia and mild hypoalbuminaemia. Diffuse megakaryocytic hypoplasia was evident within the bone marrow. We propose various hypotheses that may explain the presence of severe ectoparasite infection, skin disease and poor body condition in this woylie. Given the potential deleterious effects of parasite infection, the importance of monitoring parasites cannot be over-emphasised., Graphical abstract Image 1, Highlights • Severe ectoparasite infestation, skin disease and poor body condition in a woylie. • Trypanosoma copemani genotype 2 and Sarcocystis sp. identified molecularly in tissues. • Clinical signs similar to those observed during the woylie decline.

Host-parasite relationships are complex, and in wild animal populations individuals are commonly co-infected with various parasite species or intraspecific strains. While it is widely recognised that polyparasitism has the potential to reduce host fitness and increase susceptibility to predation or disease, the role of polyparasitism in influencing translocation success has never been investigated. Here we review the consequences of translocation for the host-parasite infracommunity and demonstrate how translocation-induced perturbations to within-host-parasite relationships may exacerbate the negative impacts of polyparasitism to the detriment of host health and translocation success. We also consider the ecological and immunological effects of altering host-parasite assemblages during translocation, and illustrate how the use of anti-parasitic drugs can further modify parasite infracommunity dynamics, with unintended impacts on target and non-target parasites. Importantly, as the evolutionary and ecological significance of the host-parasite relationship is increasingly recognised, we discuss the benefits of conserving parasites during fauna translocations.

Vector-borne haemoprotozoans comprise a diverse group of eukaryote single-celled organisms transmitted by haematophagous (blood-feeding) invertebrates. They can cause debilitating diseases that impact wildlife, livestock, companion animals and humans. Recent research has shown that Australian wildlife host a diverse range of haemoprotozoan species; however, to date this work has primarily been confined to a few host species or isolated populations in rural habitats. There has been little investigation into the presence of these blood parasites in wildlife inhabiting urban and peri-urban areas. In this study, blood and tissue samples and ticks were collected from wildlife in New South Wales and Western Australia. Extracted DNA samples were screened with pan-specific molecular assays to determine the presence of haemoprotozoans using amplicon metabarcoding and Sanger sequencing approaches. In addition, light microscopy was performed on blood films. Eight haemoprotozoans were identified in the present study, which included species of Babesia, Hepatozoon, Theileria and Trypanosoma. Blood samples were collected from 134 animals; 70 black rats (Rattus), 18 common brush-tailed possums (Trichosurus vulpecula), two bush rats (Rattus fuscipes), 22 chuditch (Dasyurus geoffroii), 20 long-nosed bandicoots (Perameles nasuta), one quenda (Isoodon fusciventer) and one swamp rat (Rattus lutreolus). Molecular screening of DNA extracted from blood samples identified 52.2% (95% CI: 43.8–60.5%) of individuals were positive for at least one haemoprotozoan species, with 19.4% (95% CI: 13.4–26.7%) positive for more than one species. The present study provides the first sequences of Theileria cf. peramelis from black rats and long-nosed bandicoots. Babesia lohae was identified from brush-tailed possums. Two Hepatozoon genotypes were identified from black rats and bush rats. Black rats showed the highest haemoprotozoan diversity, with five species identified. No known human pathogens that have been described in the northern hemisphere were identified in the present study, and future work is required to understand the zoonotic potential of these microbes in Australia. This work represents the first large-scale body of research using molecular tools to investigate haemoprotozoans in animals at the urban-wildland interface. Further research is needed to investigate potential consequences of infection in wildlife, particularly effects of pathogen spillover from invasive black rats to native wildlife.

Wildlife species are often treated with anti-parasitic drugs prior to translocation, despite the effects of this treatment being relatively unknown. Disruption of normal host-parasite relationships is inevitable during translocation, and targeted anti-parasitic drug treatment may exacerbate this phenomenon with inadvertent impacts on both target and non-target parasite species. Here, we investigate the effects of ivermectin treatment on communities of gastrointestinal parasites in translocated woylies (Bettongia penicillata). Faecal samples were collected at three time points (at the time of translocation, and 1 and 3 months post-translocation) and examined for nematode eggs and coccidian oocysts. Parasite prevalence and (for nematodes) abundance were estimated in both treated and untreated hosts. In our study, a single subcutaneous injection of ivermectin significantly reduced Strongyloides-like egg counts 1 month post-translocation. Strongyle egg counts and coccidia prevalence were not reduced by ivermectin treatment, but were strongly influenced by site. Likewise, month of sampling rather than ivermectin treatment positively influenced body condition in woylies post-translocation. Our results demonstrate the efficacy of ivermectin in temporarily reducing Strongyloides-like nematode abundance in woylies. We also highlight the possibility that translocation-induced changes to host density may influence coinfecting parasite abundance and host body condition post-translocation.

Background Understanding how fauna translocation and antiparasitic drug treatment impact parasite community structure within a host is vital for optimising translocation outcomes. Trypanosoma spp. and piroplasms (Babesia and Theileria spp.) are known to infect Australian marsupials, including the woylie (Bettongia penicillata). However relatively little is known about these haemoparasites, or how they respond to management practices such as translocation. We monitored haemoparasites infecting woylies for up to 12 months during two fauna translocations to supplement existing woylie populations in three different sites (Dryandra, Walcott and Warrup East) within south-western Australia between 2014 and 2016, with the aim of investigating (i) how haemoparasite prevalence, Trypanosoma spp. richness and Trypanosoma spp. community composition varied over time and between different sites following translocation; and (ii) whether ivermectin treatment indirectly impacts haemoparasite prevalence. Using molecular methods, 1211 blood samples were screened for the presence of trypanosomes, and a subset of these samples (n = 264) were also tested for piroplasms. Results Trypanosomes and piroplasms were identified in 55% and 94% of blood samples, respectively. We identified five Trypanosoma species, two Theileria species, a single species of Babesia and a novel Bodo species. Trypanosoma spp. richness and the prevalence of haemoparasite co-infection increased after translocation. Prior to translocation, Trypanosoma spp. community composition differed significantly between translocated and resident woylies within Walcott and Warrup East, but not Dryandra. Six months later, there was a significant difference between translocated and resident woylies within Dryandra, but not Walcott or Warrup East. The response of haemoparasites to translocation was highly site-specific, with predominant changes to the haemoparasite community in translocated woylies occurring within the first few months following translocation. Ivermectin treatment had no significant effect on haemoparasite prevalence. Conclusions This study contributes to our understanding of haemoparasite dynamics in woylies following translocation. The highly site-specific and rapid response of haemoparasites to translocation highlights the need to better understand what drives these effects. Given that haemoparasite prevalence and composition of translocated and resident animals changed significantly following translocation, we propose that parasite monitoring should form an essential component of translocation protocols, and such protocols should endeavour to monitor translocated hosts and cohabiting species. Electronic supplementary material The online version of this article (10.1186/s13071-019-3370-6) contains supplementary material, which is available to authorized users.

Taxonomic identification of ticks obtained during a longitudinal survey of the critically endangered marsupial, Bettongia penicillata Gray, 1837 (woylie, brush-tailed bettong) revealed a new species of Ixodes Latrielle, 1795. Here we provide morphological data for the female and nymphal life stages of this novel species (Ixodes woyliei n. sp.), in combination with molecular characterisation using the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). In addition, molecular characterisation was conducted on several described Ixodes species and used to provide phylogenetic context. Ixodes spp. ticks were collected from the two remaining indigenous B. penicillata populations in south-western Australia. Of 624 individual B. penicillata sampled, 290 (47%) were host to ticks of the genus Ixodes; specifically I. woyliei n. sp., I. australiensis Neumann, 1904, I. myrmecobii Roberts, 1962, I. tasmani Neumann, 1899 and I. fecialis Warburton & Nuttall, 1909. Of these, 123 (42%) were host to the newly described I. woyliei n. sp. In addition, 268 individuals from sympatric marsupial species (166 Trichosurus vulpecula hypoleucus Wagner, 1855 (brushtail possum), 89 Dasyurus geoffroii Gould, 1841 (Western quoll) and 13 Isoodon obesulus fusciventer Gray, 1841 (southern brown bandicoot)) were sampled for ectoparasites and of these, I. woyliei n. sp. was only found on two I. o. fusciventer. Morphological and molecular data have confirmed the first new Australian Ixodes tick species described in over 50 years, Ixodes woyliei n. sp. Based on the long-term data collected, it appears this tick has a strong predilection for B. penicillata, with 42% of Ixodes infections on this host identified as I. woyliei n. sp. The implications for this host-parasite relationship are unclear but there may be potential for a future co-extinction event. In addition, new molecular data have been generated for collected specimens of I. australiensis, I. tasmani and museum specimens of I. victoriensis Nuttall, 1916, which for the first time provides molecular support for the subgenus Endopalpiger Schulze, 1935 as initially defined. These genetic data provide essential information for future studies relying on genotyping for species identification or for those tackling the phylogenetic relationships of Australian Ixodes species.

Translocation can be stressful for wildlife. Stress may be important in fauna translocation because it has been suggested that it can exacerbate the impact of infectious disease on translocated wildlife. However, few studies explore this hypothesis by measuring stress physiology and infection indices in parallel during wildlife translocations. We analysed faecal cortisol metabolite (FCM) concentration and endoparasite parameters (nematodes, coccidians and haemoparasites) in a critically endangered marsupial, the woylie (Bettongia penicillata), 1–3 months prior to translocation, at translocation, and 6 months later. FCM for both translocated and resident woylies was significantly higher after translocation compared to before or at translocation. In addition, body condition decreased with increasing FCM after translocation. These patterns in host condition and physiology may be indicative of translocation stress or stress associated with factors independent of the translocation. Parasite factors also influenced FCM in translocated woylies. When haemoparasites were detected, there was a significant negative relationship between strongyle egg count and FCM. This may reflect the influence of glucocorticoids on the immune response to micro- and macro-parasites. Our results indicate that host physiology and infection patterns can change significantly during translocation, but further investigation is required to determine how these patterns influence translocation success.