KOALA NEWS & SCIENCE
An informative monthly newsletter about successes & important announcements in koala conservation, and the latest scientific publications about koalas.
Subscribe here: https://mailchi.mp/808fc4af1ee0/koala-news-science
First koala sighted at Lithgow in 5 years NSW 12 August
A Koala sighted by a walker in the area at Hassans Walls could be a sign of a recovering population.
Long-term research on Koalas on St Bees Island show population fluctuations due to climate, QLD 4 September
The 20+ year research project by University of Queensland and Central Queensland University on the island off Mackay has showed large peaks and declines in the koala population, which seems to be related to climate.
High numbers of native animals using wildlife underpasses 7 August
A 2 year study by Southern Cross University found 4800 medium-to-large native animals used 12 wildlife underpasses in the Port Macquarie and Grafton regions, mid North Coast of NSW.
New koala vaccination facility at Tweed Coast NSW 5 August
The new research facility at Pottsville will support koalas between their two chlamydia vaccinations before they are released to the wild. The centre has been funded by Tweed Shire Council, WWF Australia and NSW government and is operated by Currumbin Wildlife Hospital.
Protecting paddock trees for koalas NSW 10 August
Midcoast 2 Tops Landcare have created a Koala Paddock Tree Regeneration Project for landowners, which will design and provide fencing to protect the tree, while still providing shade for livestock.
Local philanthropist donates $1million to Port Stephens Koala Hospital NSW 11 August
After a 2 year delay due to COVID the new Port Stephens Koala Hospital was opened, with the announcement of the large donation by a Hunter philanthropic trust.
Koala joey rescued during floods released to wild 26 August
Gulliver was found alone near Ballina on February 28 and cared for by Friends of the Koala, supported by IFAW, until he was deemed fit for release.
Farmer rescues mother koala and joey from cattle QLD 12 August
The farmer at Gin Gin, near Bundaberg, found the distressed mother koala being attacked by cattle. He helped her, then called a wildlife carer. Mother and joey are now doing well in care.
Koala habitat workshop at Gloucester NSW 9 August
Gloucester Environment Group ran a community workshop on 3 September with leading local experts. Members of the public were shown how to conserve and create koala habitat on their land.
LATEST KOALA SCIENCE
Howard, E.M., 2022. Prevalence and molecular characterisation of Trypanosoma spp. in two wild koala populations; Moreton Bay, Queensland and Mount Lofty, South Australia (Doctoral dissertation, Murdoch University). https://researchrepository.murdoch.edu.au/id/eprint/65905/
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) (n= 89). The overall prevalence of Trypanosoma in both populations was 47.2% (76/161; 95% CI: 39.3-55.2%). The prevalence of trypanosomes in koalas from Moreton Bay was 80.6% (58/72; 95% CI: 69.5-88.9%), whereas the prevalence in koalas from Mount Lofty was significantly lower: 20.2% (18/89; 95% CI: 12.4-30.1%). Sanger sequencing of PCR positive products was performed and phylogenetic analysis conducted on the partial 18S rDNA fragments obtained. A total of 35 Trypanosoma isolates from Moreton Bay koalas were identified as Trypanosoma irwini (n= 36), with intra-specific genetic variations ranging from 0% – 2.99%. Remaining QLD isolates (n=16) were identified as Trypanosoma gilletti, with genetic distances ranging from 0% – 1.20%. These results are similar to findings from previous studies of hospitalised koalas from QLD and NSW.
All Trypanosoma isolates from the Mount Lofty population (n = 18) formed a unique, highly diverse clade within the Trypanosoma cruzi clade of trypanosomes. These novel sequences displayed a high genetic variation amongst each other (genetic distances = 0% – 7.04%) and from their most closely related species (T. sp 1EA-2008) (genetic distances = 1.90% – 7.73%). To the best of the author’s knowledge, this is the first report of trypanosomes in koalas from SA. The unique phylogenetic position of the isolates identified, associated with a relatively high genetic distance from their most closely related known Trypanosoma sp., suggests that they may potentially represent novel Trypanosoma spp.. Further analyses of full-length 18S sequences and additional loci are required to confirm this finding and reliably delimit the species.
Sanger sequencing of seven PCR positive isolates from Moreton Bay koalas revealed mixed chromatograms and were excluded from phylogenetic analyses. Further analyses using next-generation metabarcoding are required to identify and characterise mixed trypanosome infections in all positive samples detected in the present study, particularly those that produced mixed Sanger sequencing chromatograms.
This study provides valuable novel baseline data which will contribute to the growing knowledge base of Australian trypanosomes, and future studies on the potential impact of Trypanosoma spp. (with and without concurrent infectious diseases) on the health and conservation of koalas.
Kayesh, M.E.H., Hashem, M.A., Maetani, F., Goto, A., Nagata, N., Kasori, A., Imanishi, T. and Tsukiyama-Kohara, K., 2022. Molecular Insights into Innate Immune Response in Captive Koala Peripheral Blood Mononuclear Cells Co-Infected with Multiple Koala Retrovirus Subtypes. Pathogens, 11(8), p.911. https://doi.org/10.3390/pathogens11080911
Koala retrovirus (KoRV) exists in both endogenous and exogenous forms and has appeared as a major threat to koala health and conservation. Currently, there are twelve identified KoRV subtypes: an endogenous subtype (KoRV-A) and eleven exogenous subtypes (KoRV-B to -I, KoRV-K, -L, and -M). However, information about subtype-related immune responses in koalas against multiple KoRV infections is limited. In this study, we investigated KoRV-subtype (A, B, C, D, and F)-related immunophenotypic changes, including CD4, CD8b, IFN-γ, IL-6, and IL-10 mRNA expression, in peripheral blood mononuclear cells (PBMCs) obtained from captive koalas (n = 37) infected with multiple KoRV subtypes (KoRV-A to F) reared in seven Japanese zoos. Based on KoRV subtype infection profiles, no significant difference in CD4 and CD8b mRNA expression was observed in the study populations. Based on the different KoRV subtype infections, we found that the IFN-γ mRNA expression in koala PMBCs differs insignificantly (p = 0.0534). In addition, IL-6 and IL-10 mRNA expression also did not vary significantly in koala PBMCs based on KoRV subtype differences. We also investigated the Toll-like receptors (TLRs) response, including TLR2–10, and TLR13 mRNA in koala PBMCs infected with multiple KoRV subtypes. Significant differential expression of TLR5, 7, 9, 10, and 13 mRNA was observed in the PBMCs from koalas infected with different KoRV subtypes. Therefore, based on the findings of this study, it is assumed that co-infection of multiple KoRV subtypes might modify the host innate immune response, including IFN-γ and TLRs responses. However, to have a more clear understanding regarding the effect of multiple KoRV subtypes on host cytokines and TLR response and pathogenesis, further large-scale studies including the koalas negative for KoRV and koalas infected with other KoRV subtypes (KoRV-A to -I, KoRV-K, -L and -M) are required.
Pearson, E.L., Mellish, S., McLeod, E.M., Sanders, B. and Ryan, J.C., 2022. Can we save Australia’s Endangered Wildlife by Increasing Species Recognition?. Journal for Nature Conservation, p.126257.
Australia’s species extinction rate is one of the highest in the world. Yet, there is limited evidence regarding people’s recognition of, and preferences and support for, Australian endangered wildlife. This paper presents survey responses from 223 Zoos Victoria visitors (response rate: 39.1 %) and 90 community members (Victoria, Australia). We examined people’s top 10 overall (global) and Australian favourite animals, and conducted an in-depth exploration of recognition of, and preferences and support for, seven Australian endangered species identified as being at risk of extinction within the next decade, including: the leadbeater’s possum (Gymnobelideus leadbeateri), eastern barred bandicoot (Perameles gunnii), helmeted honeyeater (Lichenostomus melanops cassidix), southern corroboree frog (Pseudophryne corroboree), Lord Howe Island (LHI) stick insect (Dryococelus australis), Tasmanian devil (Sarcophilus harrisii), and the orange-bellied parrot (Neophema chrysogaster). Results indicate that the only Australian animals to feature in the overall top 10 favourite list were the kangaroo (ranked 9th for both sample groups) and koala (ranked 6th and 10th for the community and zoo sample, respectively). The Tasmanian devil had the highest rate of recognition (>86 %), in comparison to the remaining six species (1.2–7.3 % across both samples). Endangered species were not prominent in the top favourite Australian species. Australian endangered species’ likeability ratings typically followed the pattern of mammals being most likeable (Tasmanian devil and leadbeater’s possum), followed by birds, frogs, and insects (helmeted honeyeater, southern corroboree frog, and LHI stick insect). Importantly, for most endangered native species featured (4/7 and 6/7; zoo and community, respectively), simply being able to recognise species significantly (p <.05) increased people’s willingness to support their conservation. Findings underscore several powerful opportunities for future conservation programs to contribute to Australian endangered species conservation by striving to increase public familiarity with Australian species most at risk of extinction.
KOALA SCIENCE IN BRIEF:
Higgins, D., Govendir, M., Krockenberger, M., Ward, M. and Toribio, J.A., 2022. Leading research for animal health, welfare, and biosecurity. American Journal of Veterinary Research, 83(9). https://doi.org/10.2460/ajvr.22.07.0116
Previous Koala News & Science here: http://www.wildkoaladay.com.au/koala-news-science/koala-news-science-july-2022/
Written by Janine Duffy President, Koala Clancy Foundation.
with support from Cheryl Egan, Organiser, Wild Koala Day.
Please send your positive, important news & publications to email@example.com before 29th of each month for possible inclusion.