PubMed | Vepalabs, University of Queensland, Australia Zoo Wildlife Hospital and University of New South Wales
Type: Journal Article | Journal: Journal of comparative pathology | Year: 2016
Chlamydiosis is a common infectious disease of koalas (Phascolarctos cinereus), but Chlamydia spp. have not yet been demonstrated to cause pneumonia in these animals. A juvenile male koala died following an episode of respiratory disease. At necropsy examination, the lung tissue was consolidated. Microscopical lesions in the lung included pyogranulomatous bronchopneumonia, proliferation of bronchiolar and alveolar epithelium and interstitial fibrosis. Hyperplastic bronchiolar epithelial cells contained aggregates of small basophilic punctate organisms, which were confirmed as chlamydiae by transmission electron microscopy and immunohistochemistry. Real-time polymerase chain reaction identified these as Chlamydia pecorum. This report provides the best evidence to date of chlamydial infection causing pneumonia in a koala, and the first evidence that C. pecorum is capable of infecting the bronchiolar epithelium of the koala.
Kollipara A.,Queensland University of Technology |
George C.,Queensland University of Technology |
Hanger J.,Australia Zoo Wildlife Hospital |
Loader J.,Australia Zoo Wildlife Hospital |
And 3 more authors.
Vaccine | Year: 2012
Chlamydial infections represent a major threat to the long-term survival of the koala and a successful vaccine would provide a valuable management tool. Vaccination however has the potential to enhance inflammatory disease in animals exposed to a natural infection prior to vaccination, a finding in early human and primate trials of whole cell vaccines to prevent trachoma. In the present study, we vaccinated both healthy koalas as well as clinically diseased koalas with a multi-subunit vaccine consisting of Chlamydia pecorum MOMP and NrdB mixed with immune stimulating complex as adjuvant. Following vaccination, there was no increase in inflammatory pathological changes in animals previously infected with Chlamydia. Strong antibody (including neutralizing antibodies) and lymphocyte proliferation responses were recorded in all vaccinated koalas, both healthy and clinically diseased. Vaccine induced antibodies specific for both vaccine antigens were observed not only in plasma but also in ocular secretions. Our data shows that an experimental chlamydial vaccine is safe to use in previously infected koalas, in that it does not worsen infection-associated lesions. Furthermore, the prototype vaccine is effective, as demonstrated by strong levels of neutralizing antibody and lymphocyte proliferation responses in both healthy and clinically diseased koalas. Collectively, this work illustrates the feasibility of developing a safe and effective Chlamydia vaccine as a tool for management of disease in wild koalas. © 2012 Elsevier Ltd.
Craig A.P.,University of New South Wales |
Hanger J.,Australia Zoo Wildlife Hospital |
Loader J.,Australia Zoo Wildlife Hospital |
Ellis W.A.H.,University of Queensland |
And 6 more authors.
Vaccine | Year: 2014
Background: Many koala populations around Australia are in serious decline, with a substantial component of this decline in some Southeast Queensland populations attributed to the impact of Chlamydia. A Chlamydia vaccine for koalas is in development and has shown promise in early trials. This study contributes to implementation preparedness by simulating vaccination strategies designed to reverse population decline and by identifying which age and sex category it would be most effective to target. Methods: We used field data to inform the development and parameterisation of an individual-based stochastic simulation model of a koala population endemic with Chlamydia. The model took into account transmission, morbidity and mortality caused by Chlamydia infections. We calibrated the model to characteristics of typical Southeast Queensland koala populations. As there is uncertainty about the effectiveness of the vaccine in real-world settings, a variety of potential vaccine efficacies, half-lives and dosing schedules were simulated. Results: Assuming other threats remain constant, it is expected that current population declines could be reversed in around 5-6 years if female koalas aged 1-2 years are targeted, average vaccine protective efficacy is 75%, and vaccine coverage is around 10% per year. At lower vaccine efficacies the immunological effects of boosting become important: at 45% vaccine efficacy population decline is predicted to reverse in 6 years under optimistic boosting assumptions but in 9 years under pessimistic boosting assumptions. Terminating a successful vaccination programme at 5 years would lead to a rise in Chlamydia prevalence towards pre-vaccination levels. Conclusion: For a range of vaccine efficacy levels it is projected that population decline due to endemic Chlamydia can be reversed under realistic dosing schedules, potentially in just 5 years. However, a vaccination programme might need to continue indefinitely in order to maintain Chlamydia prevalence at a sufficiently low level for population growth to continue. © 2014 Elsevier Ltd.
News Article | August 31, 2016
The largest survey of its kind in the southern hemisphere examined 61 species, including 370 inidvidual birds from eastern Australia. Dr Kathy Townsend from the School of Biomedical Sciences and the Moreton Bay Research Station said 30 per cent of species investigated had ingested marine debris. "How the birds feed effects the type of debris they ingest, along with their habitat," Dr Townsend said. "For example, pursuit-diving species such as shags and cormorants ingested things like fishing hooks and sinkers, while surface-feeders such as albatross and short-tailed shearwaters ingested buoyant plastics and balloons. "The study showed that marine birds were highly selective of the physical characteristics, types and colours of debris they ingest." Dr Townsend said that for the short-tailed shearwater their unorthodox diet was likely a case of mistaken identity. "These birds feed extensively on red arrow squid and they were found to particularly favour red and orange balloons which may look similar when they are foraging." Lead author Lauren Roman, now with the Institute for Marine and Antarctic Studies in Tasmania, conducted research as part of her UQ Honours thesis. Ms Roman said species which ingested debris included the near-threatened Buller's albatross (Thalassarche bulleri) and shy albatross (Thalassarche cauta). The vulnerable Westland petrel (Procellaria westlandica) and Gould's petrel (Pterodroma leucoptera) were also found to feed on rubbish. Ms Roman said the birds investigated in the study were collected dead by citizen scientists and wildlife care groups across eastern Australia and the contents of their stomach examined during necropsies. "Pollution of the world's oceans is having direct impacts on marine birds but the extent is yet to be fully investigated in Australia," she said. Australian Seabird Rescue, Pelican and Seabird Rescue, Currumbin Wildlife Hospital, RSPCA Wacol Wildlife Hospital, the Queensland Department of Environment and Heritage Protection, Australia Zoo Wildlife Hospital and Queensland Museum all contributed to the survey. The study has been published in PloS One. More information: Anthropogenic Debris Ingestion by Avifauna in Eastern Australia. dx.doi.org/10.1371/journal.pone.0158343
Davies N.,University of Queensland |
Gillett A.,Australia Zoo Wildlife Hospital |
McAlpine C.,University of Queensland |
Seabrook L.,University of Queensland |
And 4 more authors.
Journal of Endocrinology | Year: 2013
Environmental changes result in physiological responses of organisms, which can adversely affect population dynamics and reduce resistance to disease. These changes are expressed in chronic levels of stress. The measurement of glucocorticoid (GC) concentrations in faeces is a non-invasive method for monitoring stress in wildlife. The metabolism and excretion of steroids differ significantly between species and, as a consequence, non-invasive methods must be physiologically validated for each species. Koalas (Phascolarctos cinereus) are declining in numbers through much of their range. The role of chronic stress in koala populations has not been identified. Prior to the assessment of faecal GC concentrations in wild koala populations, the excretion timing and concentrations of GCs need to be determined. In this study, we assessed a method for identifying and measuring the concentrations of GC metabolites in faecal pellets of captive koalas following ACTH treatment. The results show that an elevation of plasma cortisol concentrations, using sustained release of ACTH, results in elevated concentrations of faecal cortisol/cortisol metabolites. Taking into account the excretion time lag, an increase in faecal cortisol metabolite concentrations corresponds to the release of GCs from the adrenal cortex as early as 36 h before faecal pellet collection. The calculations of steroid partitioning of plasma cortisol showed that the ACTH-stimulated values were significantly different from the control values for the concentrations of free, corticosteroid-binding globulin-bound and albumin-bound cortisol. This study validates the use of faecal cortisol analysis to assess the activity of the hypothalamo-pituitary-adrenocortical axis in freshly collected koala faecal pellets and indicates that the method should be suitable to assess the adrenocortical status of koalas in wild populations. © 2013 Society for Endocrinology.
PubMed | University of New South Wales, Murdoch University and Australia Zoo Wildlife Hospital
Type: Journal Article | Journal: Parasites & vectors | Year: 2016
To date, little has been documented about microorganisms harboured within Australian native ticks or their pathogenic potential. Recently, a Borrelia sp. related to the Relapsing Fever (RF) group was identified in a single tick removed from a wild echidna (Tachyglossus aculeatus). The present study investigated the presence of Borrelia in 97 Bothriocroton concolor ticks parasitizing echidnas in Queensland, New South Wales, and Victoria, Australia, using nested PCR with Borrelia-specific primers targeting the 16S rRNA (16S) and flaB genes.Borrelia-specific PCR assays confirmed the presence of a novel Borrelia sp. related to the RF and reptile-associated (REP) spirochaetes in 38 (39%) B. concolor ticks. This novel Borrelia sp. was identified in 41% of the B. concolor ticks in Queensland and New South Wales, but not in any ticks from Victoria. The resulting flaB sequences (407bp) were 88 and 86% similar to the flaB sequences from Borrelia turcica and Borrelia hermsii, respectively. Of the ticks confirmed as Borrelia-positive following the flaB assay, 28 were positive with the 16S assay. Phylogenetic analysis of the 16S sequences (1097bp) suggests that these sequences belong to a novel Borrelia sp., which forms a unique monophyletic clade that is similar to, but distinct from, RF Borrelia spp. and REP-associated Borrelia spp.We conclude that the novel Borrelia sp. identified in this study does not belong to the Borrelia burgdorferi (sensu lato) complex, and that the phylogenetic analysis of the partial 16S gene sequences suggests it forms a unique monophyletic cluster in the genus Borrelia, potentially forming a fourth major group in this genus associated with monotremes in Australia. However, a thorough molecular characterisation will be required to confirm the phylogenetic position of this unique Borrelia sp. The zoonotic potential and pathogenic consequences of this novel Borrelia sp. are unknown at the current time.
PubMed | Vepalabs, Murdoch University, Australia Zoo Wildlife Hospital and University of Brasilia
Type: | Journal: Veterinary parasitology | Year: 2016
Little is known about the genetic diversity and pathogenicity of trypanosomes in Australian bats. Recently a novel trypanosome species was identified in an adult female little red flying fox (Pteropus scapulatus) with clinical and pathological evidence of trypanosomosis. The present study used morphology and molecular methods to demonstrate that this trypanosome is a distinct species and we propose the name Trypanosoma teixeirae sp. n. Morphological comparison showed that its circulating trypomastigotes were significantly different from those of Trypanosoma pteropi and Trypanosoma hipposideri, two species previously described from Australian bats. Genetic information was not available for T. pteropi and T. hipposideri but phylogenetic analyses at the 18S ribosomal RNA (rRNA) and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) loci indicated that T. teixeirae sp. n. was genetically distinct and clustered with other bat-derived trypanosome species within the Trypanosoma cruzi clade.
News Article | August 29, 2016
The painful and intractable disease is having a devastating impact on populations of Australia's beloved marsupial. Specialist koala vets are using two antibiotics – Baytril and Chloramphenicol 150. However, there is less than two years' supply of Chloramphenicol 150 remaining and the drug is no longer on the market. Neither of the current treatments works in all cases of chlamydial disease and a new treatment is urgently needed. Microbiologist Dr Willa Huston, of the University of Technology Sydney, with collaborators at Australia Zoo Wildlife Hospital and elsewhere, has identified a chemical that paves the way for a new antibiotic to save koalas' lives. In extensive laboratory tests on tissue samples from chlamydia-infected koalas, the researchers found the compound to be highly successful at killing the bacteria and low in toxicity against koala cells. "It's really urgent now that we put a concerted effort into developing this treatment further," says Dr Huston. "Manufacture [of the old one] has stopped, supply has stopped, and it can take years to develop a new drug. "We are in a desperate search to find new, effective treatments and test other drugs that might help koalas recover from this horrible disease." Koalas are listed as a vulnerable species in NSW and Queensland. Fewer than 100,000 remain in the wild in Australia and are at risk from habitat loss, motor vehicle trauma, domestic dog attacks and, increasingly, disease. Dr Huston says as many as one in five koalas in the wild in south-east Queensland and northern NSW have severe chlamydiosis; some studies have found as many as nine in 10 koalas with chlamydial infections. Wildlife veterinarians are also reporting that the disease is spreading south – infections have been reported in Victoria, where koala populations are larger, and South Australia, where koalas are listed as "rare". Male and female koalas are affected by two species of Chlamydia – C. pecorum and C. pneumoniae. The first causes eye disease, including inflammation and discharge, or urogenital disease, including cystitis, urinary incontinence (known as "wet bottom") and fibrosis, which can cause infertility. The second strain causes severe respiratory illness. Any new drug must be able to treat chlamydiosis while minimising side effects. As a specialised eucalyptus herbivore, the koala's metabolism is uniquely placed to deal with toxic plant compounds. However, koalas respond poorly to antibiotic treatments commonly used in humans, suffering side effects such as emaciation, and typically fail to recover completely from disease. Dr Huston and her team are fine-tuning the chemical make-up of their discovery before they begin testing on sick koalas. "Time is running out. We all treasure our koalas and we need to do everything we can to cure this disease." The paper is published in the Nature journal Scientific Reports. More information: Amba Lawrence et al. Chlamydia Serine Protease Inhibitor, targeting HtrA, as a New Treatment for Koala Chlamydia infection, Scientific Reports (2016). DOI: 10.1038/srep31466
Barker C.J.,Kelvin Institute |
Gillett A.,Australia Zoo Wildlife Hospital |
Polkinghorne A.,Kelvin Institute |
Timms P.,Kelvin Institute
Veterinary Microbiology | Year: 2013
As a dietary source, the foliage of Eucalyptus spp. is low in available protein and carbohydrate while containing polyphenolic compounds that interfere with enzymatic digestion. To overcome this, the koala ( Phascolarctos cinereus) has evolved a range of anatomical and physiological adaptations to assist with digestion and absorption of nutrients from this food source. Microbial fermentation of partially digested eucalyptus leaves is thought to be critical in this process, however, little is known about the composition and diversity of microorganisms that are associated with digestive health in this native species. In this study, we performed 16S rRNA gene pyrosequencing of caecum, colon and faecal pellet samples from two wild, free ranging, Queensland koalas. Our results reveal a highly complex and diverse ecosystem with considerable intra-individual variation. Although samples were dominated by sequences from the Bacteroidetes and Firmicutes phyla there was considerable variation at the genus level. This study is the first non-culture based microbiota analysis, using 454-amplicon pyrosequencing, and provides preliminary data to expand our understanding of the koala hindgut. © 2013 Elsevier B.V.
PubMed | Office of Environment and Heritage NSW, University of Queensland, Australia Zoo Wildlife Hospital, Griffith University and 3 more.
Type: Journal Article | Journal: Biology letters | Year: 2016
Daylight saving time (DST) could reduce collisions with wildlife by changing the timing of commuter traffic relative to the behaviour of nocturnal animals. To test this idea, we tracked wild koalas (Phascolarctos cinereus) in southeast Queensland, where koalas have declined by 80% in the last 20 years, and compared their movements with traffic patterns along roads where they are often killed. Using a simple model, we found that DST could decrease collisions with koalas by 8% on weekdays and 11% at weekends, simply by shifting the timing of traffic relative to darkness. Wildlife conservation and road safety should become part of the debate on DST.