{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T08:32:33Z","timestamp":1793435553465,"version":"4.5.0"},"reference-count":36,"publisher":"Wildlife Disease Association","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Wildlife Diseases"],"published-print":{"date-parts":[[2022,1,4]]},"abstract":"<jats:p>Testis asymmetry, in which the testes in an individual differ in size, has recently been reported in koalas (Phascolarctos cinereus) in the Mount Lofty Ranges population of South Australia. We describe the morphology and histology of both testes from affected individuals in this population (n=56) and the parameters of koalas with normal-sized testes based on age and breeding season (n=56). Morphologic measurements included testis weight, length, width, and volume; histologic parameters included seminiferous tubule diameter, seminiferous epithelial height, and seminiferous tubule (interstitial tissue ratio and presence or absence of spermatozoa). Of the 56 koalas with intraindividual variation in testes size, 47 were classified as asymmetric and nine as microtestes. For koalas with asymmetric testes, all morphologic parameters were significantly decreased in the smaller testes compared with normal-sized testes, but for the histologic parameters, only seminiferous tubule diameter was significantly less. Histopathologic examination of the asymmetric testes showed 38 with normal parenchyma histologically indistinguishable between intraindividual testes, four with degeneration and atrophy, and three with hypoplasia, whereas examination of microtestes showed degeneration and atrophy in seven, hypoplasia in one, and aplasia in one. No association of testis size difference with Chlamydia pecorum infection was found in a subset of animals. For the 56 koalas with normal-sized testes, morphologic parameters were found to increase with age, and juvenile and young adults were found to have smaller seminiferous tubule diameters than adults. No differences were found between testes of koalas in the breeding and nonbreeding season. Overall, these findings indicate that testis asymmetry in koalas from the Mount Lofty Ranges population is common but not associated with decreased function, except where testis malformations such as hypoplasia or aplasia occur or when parenchyma has been disrupted by acquired disease.<\/jats:p>","DOI":"10.7589\/jwd-d-21-00055","type":"journal-article","created":{"date-parts":[[2022,1,4]],"date-time":"2022-01-04T06:53:59Z","timestamp":1641279239000},"page":"158-167","source":"Crossref","is-referenced-by-count":3,"title":["TESTIS ABNORMALITIES IN A POPULATION OF SOUTH AUSTRALIAN KOALAS (PHASCOLARCTOS CINEREUS)"],"prefix":"10.7589","volume":"58","author":[{"given":"Chloe","family":"Buchanan","sequence":"first","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucy","family":"Woolford","sequence":"additional","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tamsyn","family":"Stephenson","sequence":"additional","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mara","family":"Hoebergen","sequence":"additional","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jessica H.","family":"Kovac","sequence":"additional","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William G.","family":"Breed","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Faculty of Sciences, North Terrace Campus, University of Adelaide, Adelaide, South Australia 5005, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natasha","family":"Speight","sequence":"additional","affiliation":[{"name":"School of Animal and Veterinary Sciences, Faculty of Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, South Australia 5371, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4415","reference":[{"key":"15","doi-asserted-by":"crossref","unstructured":"GJ Kenagy  and SC Trombulak  \"J Mammal.\"  67, \"Size and function of mammalian testes in relation to body size.\" 1 (1986)","DOI":"10.2307\/1380997"},{"key":"29","doi-asserted-by":"crossref","unstructured":"KN Speight, A Polkinghorne, R Penn, et al.  \"J Wildl Dis.\"  52, \"Prevalence and pathologic features of Chlamydia pecorum infections in South Australian koalas (Phascolarctos cinereus).\" 301 (2016)","DOI":"10.7589\/2015-05-120"},{"key":"13","doi-asserted-by":"crossref","unstructured":"SD Johnston, HH Deif, A McKinnon, et al.  \"Vet Pathol.\"  52, \"Orchitis and epididymitis in koalas (Phascolarctos cinereus) infected with Chlamydia pecorum.\" 1254 (2015)","DOI":"10.1177\/0300985815570069"},{"key":"31","doi-asserted-by":"crossref","unstructured":"DA Taggart, GA Shimmin, JR Ratcliff, et al.  \"J Zool.\"  266, \"Seasonal changes in the testis, accessory glands and ejaculate characteristics of the southern hairy-nosed wombat, Lasiorhinus latifrons (marsupialia: Vombatidae).\" 95 (2005)","DOI":"10.1017\/S0952836905006722"},{"key":"1","doi-asserted-by":"crossref","unstructured":"CD Allen, DL de Villiers, BD Manning, et al.  \"Reprod Fertil Dev.\"  22, \"Seasonal reproduction in wild and captive male koala (Phascolarctos cinereus) populations in south-east Queensland.\" 695 (2010)","DOI":"10.1071\/RD09113"},{"key":"2","doi-asserted-by":"crossref","unstructured":"W Blanshard  and K Bodley  \"Medicine of Australian mammals: An Australian perspective.\"  \"Koalas.\" 334 (2008)","DOI":"10.1071\/978064309797111.227.328.2008.11"},{"key":"3","doi-asserted-by":"crossref","unstructured":"WG Breed, CM Leigh, M Ricci,  \"J Anat.\"  198, \"The structural organisation of sperm head components of the wombat and koala (suborder: Vombatiformes): An enigma amongst marsupials.\" 57 (2001)","DOI":"10.1046\/j.1469-7580.2001.19810057.x"},{"key":"4","doi-asserted-by":"crossref","unstructured":"GM Cleva, GM Stone, RK Dickens,  \"Reprod Fertil Dev.\"  6, \"Variation in reproductive parameters in the captive male koala (Phascolarctos cinereus).\" 713 (1994)","DOI":"10.1071\/RD9940713"},{"key":"5","doi-asserted-by":"crossref","unstructured":"R Cristescu, V Cahill, WB Sherwin, et al.  \"Wildl Res.\"  36, \"Inbreeding and testicular abnormalities in a bottlenecked population of koalas (Phascolarctos cinereus).\" 299 (2009)","DOI":"10.1071\/WR08010"},{"key":"6","unstructured":"HHA Deif,  \"Chlamydial disease of the male koala (Phascolarctos cinereus) reproductive tract.\"  115 (2011)"},{"key":"7","doi-asserted-by":"crossref","unstructured":"WAH Ellis  and FB Bercovitch  \"Behav Ecol Sociobiol.\"  65, \"Body size and sexual selection in the koala.\" 1229 (2011)","DOI":"10.1007\/s00265-010-1136-4"},{"key":"8","doi-asserted-by":"crossref","unstructured":"J Fabijan, N Sarker, N Speight, et al.  \"J Comp Pathol.\"  176, \"Pathological findings in koala retrovirus-positive koalas (Phascolarctos cinereus) from northern and southern Australia.\" 50 (2020)","DOI":"10.1016\/j.jcpa.2020.02.003"},{"key":"9","doi-asserted-by":"crossref","unstructured":"JH Fabijan, C Caraguel, M Jelocnik, et al.  \"Sci Rep.\"  9, \"Chlamydia pecorum prevalence in South Australian koala (Phascolarctos cinereus) populations: Identification and modelling of a population free from infection.\" 6261 (2019)","DOI":"10.1038\/s41598-019-42702-z"},{"key":"10","doi-asserted-by":"crossref","unstructured":"HR Harding, FN Carrick, CD Shorey,  \"Cell Tissue Res.\"  221, \"Crystalloid inclusions in the Sertoli cell of the koala, Phascolarctos cinereus (Marsupialia).\" 633 (1982)","DOI":"10.1007\/BF00215707"},{"key":"11","doi-asserted-by":"crossref","unstructured":"LS Hulse, D Hickey, JM Mitchell, et al.  \"J Vet Diagn Invest.\"  30, \"Development and application of two multiplex real-time PCR assays for detection and speciation of bacterial pathogens in the koala.\" 523 (2018)","DOI":"10.1177\/1040638718770490"},{"key":"12","doi-asserted-by":"crossref","unstructured":"RW. Inns,  \"J Reprod Fertil.\"  66, \"Seasonal changes in the accessory reproductive system and plasma testosterone levels of the male tammar wallaby, Macropus eugenii, in the wild.\" 675 (1982)","DOI":"10.1530\/jrf.0.0660675"},{"key":"14","doi-asserted-by":"crossref","unstructured":"DA Kamstock, EJ Ehrhart, DM Getzy, et al.  \"Vet Pathol.\"  48, \"Recommended guidelines for submission, trimming, margin evaluation, and reporting of tumor biopsy specimens in veterinary surgical pathology.\" 19 (2011)","DOI":"10.1177\/0300985810389316"},{"key":"16","doi-asserted-by":"crossref","unstructured":"JB Kerr, CM Knell, DC Irby,  \"Anat Embryol.\"  176, \"Ultrastructure and possible function of giant crystalloids in the Sertoli cell of the juvenile and adult koala (Phascolarctos cinereus).\" 213 (1987)","DOI":"10.1007\/BF00310054"},{"key":"17","doi-asserted-by":"crossref","unstructured":"M Krasi\u0144ska, Z G\u017cejewski, E Czykier, et al.  \"Acta Theriol.\"  54, \"Changes of weight and size of European bison testes during postnatal development.\" 111 (2009)","DOI":"10.1007\/BF03193167"},{"key":"18","unstructured":"AK Lee  and RW Martin  \"The koala: A natural history.\"  102 (1988)"},{"key":"19","doi-asserted-by":"crossref","unstructured":"J Marsh, A Kollipara, P Timms, et al.  \"BMC Microbiol.\"  11, \"Novel molecular markers of Chlamydia pecorum genetic diversity in the koala (Phascolarctos cinereus).\" 77 (2011)","DOI":"10.1186\/1471-2180-11-77"},{"key":"20","unstructured":"RW Martin  and KA Handasyde  \"Biology of the koala.\"  \"Population dynamics of the koala (Phascolarctos cinereus) in southeastern Australia.\" 75 (1990)"},{"key":"21","unstructured":"M. Montgomery,  \"Male reproductive characteristics and inbreeding depression in koala populations.\"  167 (2002)"},{"key":"22","doi-asserted-by":"crossref","unstructured":"M Oishi, M Takahashi, H Amasaki, et al.  \"J Anat.\"  222, \"The seminiferous epithelial cycle and microanatomy of the koala (Phascolarctos cinereus) and southern hairy-nosed wombat (Lasiorhinus latifrons) testis.\" 380 (2013)","DOI":"10.1111\/joa.12020"},{"key":"23","doi-asserted-by":"crossref","unstructured":"SA Ramm  and L Sch\u00e4rer  \"Biol Rev.\"  89, \"The evolutionary ecology of testicular function: Size isn't everything.\" 874 (2014)","DOI":"10.1111\/brv.12084"},{"key":"24","unstructured":"AC. Robinson,  \"The koala: Proceedings of the Taronga symposium on koala biology, management and medicine, 11\u201312 March.\"  \"The koala in South Australia.\" 132 (1978)"},{"key":"25","doi-asserted-by":"crossref","unstructured":"AM Seymour, ME Montgomery, BH Costello, et al.  \"Anim Conserv.\"  4, \"High effective inbreeding coefficients correlate with morphological abnormalities in populations of South Australian koalas (Phascolarctos cinereus).\" 211 (2001)","DOI":"10.1017\/S1367943001001251"},{"key":"26","doi-asserted-by":"crossref","unstructured":"T Shojima, R Yoshikawa, S Hoshino, et al.  \"J Virol.\"  87, \"Identification of a novel subgroup of koala retrovirus from koalas in Japanese Zoos.\" 9943 (2013)","DOI":"10.1128\/JVI.01385-13"},{"key":"27","doi-asserted-by":"crossref","unstructured":"LW Simmons  and JL Fitzpatrick  \"Reproduction.\"  144, \"Sperm wars and the evolution of male fertility.\" 519 (2012)","DOI":"10.1530\/REP-12-0285"},{"key":"28","doi-asserted-by":"crossref","unstructured":"KN Speight, P Hicks, C Graham, et al.  \"Aust Vet J.\"  96, \"Necropsy findings of koalas from the Mount Lofty Ranges population in South Australia.\" 188 (2018)","DOI":"10.1111\/avj.12690"},{"key":"30","doi-asserted-by":"crossref","unstructured":"D Taggart, WG Breed, PD Temple-Smith, et al.  \"Sperm competition and sexual selection.\"  \"Reproduction, mating strategies, and sperm competition in marsupials and monotremes.\" 623 (1998)","DOI":"10.1016\/B978-012100543-6\/50040-4"},{"key":"32","doi-asserted-by":"crossref","unstructured":"RE Tarlinton, J Fabijan, F Hemmatzadeh, et al.  \"Conserv Genet.\"  22, \"Transcriptomic and genomic variants between koala populations reveals underlying genetic components to disorders in a bottlenecked population.\" 329 (2021)","DOI":"10.1007\/s10592-021-01340-7"},{"key":"33","unstructured":"PD Temple-Smith  and DA Taggart  \"Biology of the koala.\"  \"On the male generative organs of the koala (Phascolarctos cinerus): An update.\" 33 (1990)"},{"key":"34","doi-asserted-by":"crossref","unstructured":"H Tyndale-Biscoe  and M Renfree  \"Reproductive physiology of marsupials.\"  \"Male anatomy and spermatogenesis.\" 124 (1987)","DOI":"10.1017\/CBO9780511623493"},{"key":"35","doi-asserted-by":"crossref","unstructured":"D Vagan\u00e9e, F Daems, W Aerts, et al.  \"BJU Int.\"  122, \"Testicular asymmetry in healthy adolescent boys.\" 654 (2018)","DOI":"10.1111\/bju.14174"},{"key":"36","doi-asserted-by":"crossref","unstructured":"ZH. Yu,  \"Int J Androl.\"  21, \"Asymmetrical testicular weights in mammals, birds, reptiles and amphibia.\" 53 (1998)","DOI":"10.1046\/j.1365-2605.1998.00088.x"}],"container-title":["Journal of Wildlife Diseases"],"original-title":[],"deposited":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T07:55:48Z","timestamp":1793433348000},"score":1,"resource":{"primary":{"URL":"https:\/\/bioone.org\/journals\/journal-of-wildlife-diseases\/volume-58\/issue-1\/JWD-D-21-00055\/TESTIS-ABNORMALITIES-IN-A-POPULATION-OF-SOUTH-AUSTRALIAN-KOALAS-PHASCOLARCTOS\/10.7589\/JWD-D-21-00055.full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,4]]},"references-count":36,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2022,1,1]]}},"URL":"https:\/\/doi.org\/10.7589\/jwd-d-21-00055","relation":{},"ISSN":["0090-3558","1943-3700"],"issn-type":[{"value":"0090-3558","type":"print"},{"value":"1943-3700","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,4]]}}}