Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales, Australia.
The Westmead Institute for Medical Research, Westmead, New South Wales, Australia.
mSphere. 2019 Jun 5;4(3):e00216-19. doi: 10.1128/mSphere.00216-19.
molecular type VGII is one of the etiologic agents of cryptococcosis, a systemic mycosis affecting a wide range of host species. Koalas () exhibit a comparatively high prevalence of cryptococcosis (clinical and subclinical) and nasal colonization, particularly in captivity. In Australia, disease associated with VGII is typically confined to Western Australia and the Northern Territory (with sporadic cases reported in eastern Australia), occupying an enigmatic ecologic niche. A cluster of cryptococcosis in captive koalas in eastern Australia (five confirmed cases, a further two suspected), caused predominantly by VGII, was investigated by surveying for subclinical disease, culturing koala nasal swabs and environmental samples, and genotyping cryptococcal isolates. restriction fragment length polymorphism analysis, multilocus sequence typing (MLST), and whole-genome sequencing (WGS) provided supportive evidence that the transfer of koalas from Western Australia and subsequently between several facilities in Queensland spread VGII into uncontaminated environments and environments in which VGI was endemic. MLST identified VGII isolates as predominantly sequence type 7, while WGS further confirmed a limited genomic diversity and revealed a basal relationship with isolates from Western Australia. We hypothesize that this represents a founder effect following the introduction of a koala from Western Australia. Our findings suggest a possible competitive advantage for VGII over VGI in the context of this captive koala environment. The ability of koalas to seed VGII into new environments has implications for the management of captive populations and movements of koalas between zoos. molecular type VGII is one of the causes of cryptococcosis, a severe fungal disease that is acquired from the environment and affects many host species (including humans and koalas). In Australia, disease caused by VGII is largely confined to western and central northern parts of the country, with sporadic cases reported in eastern Australia. We investigated an unusual case cluster of cryptococcosis, caused predominantly by VGII, in a group of captive koalas in eastern Australia. This research identified that the movements of koalas between wildlife parks, including an initial transfer of a koala from Western Australia, introduced and subsequently spread VGII in this captive environment. The spread of this pathogen by koalas could also impact other species, and these findings are significant in the implications they have for the management of koala transfers and captive environments.
分子类型 VGII 是隐球菌病的病原体之一，隐球菌病是一种影响广泛宿主物种的系统性真菌感染。考拉（）患有隐球菌病（临床和亚临床）和鼻腔定植的比例相对较高，尤其是在圈养环境中。在澳大利亚，与 VGII 相关的疾病通常局限于西澳大利亚州和北领地（在澳大利亚东部也有零星病例报告），占据了一个神秘的生态位。一组在澳大利亚东部圈养考拉中发生的隐球菌病（确诊病例 5 例，疑似病例 2 例），主要由 VGII 引起，通过调查亚临床疾病、培养考拉鼻腔拭子和环境样本以及对隐球菌分离株进行基因分型进行了研究。限制性片段长度多态性分析、多位点序列分型（MLST）和全基因组测序（WGS）提供了有力的证据表明，从西澳大利亚州转移来的考拉，随后在昆士兰州的几个设施之间转移，将 VGII 传播到了未受污染的环境和原本流行 VGI 的环境中。MLST 将 VGII 分离株鉴定为主要序列类型 7，而 WGS 进一步证实了有限的基因组多样性，并揭示了与来自西澳大利亚州的分离株的基本关系。我们假设这是在引入一只来自西澳大利亚州的考拉后出现的奠基者效应。我们的研究结果表明，在这种圈养考拉环境中，VGII 相对于 VGI 可能具有竞争优势。考拉将 VGII 传播到新环境的能力对圈养种群的管理以及考拉在动物园之间的移动具有重要意义。
