Faculty of Science/Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia.
Koala Hospital Port Macquarie, Koala Conservation Australia, Port Macquarie, New South Wales, Australia.
PeerJ. 2023 Aug 15;11:e15842. doi: 10.7717/peerj.15842. eCollection 2023.
Transmission of between koalas is a potential risk in field capture or rehabilitation settings, where koalas are held in proximity to each other, or equipment is shared between animals. Given the impact of on koala welfare and population viability it is surprising that quarantine and disinfection protocols in a koala rehabilitation facility or capture settings have not previously been evaluated. This study aimed to evaluate an approach, based on the detection of chlamydial DNA and cell viability, to determine the degree of environmental contamination within a koala care facility. Various fomite sites associated with koala care at a koala rehabilitation facility in New South Wales, Australia were identified as potential sources of chlamydial contamination, following exposure to koalas known to be infected with . Fomite sites were swabbed following exposure, and again after decontamination procedures were carried out. Samples were tested for the presence of chlamydial DNA using qPCR and viability using both RT-qPCR and cell culture. From a total of 239 sampling events, 30 tested qPCR positive for chlamydial DNA, with 19 and 11 samples corresponding to pre-decontamination and post-decontamination events respectively. Detection of chlamydial DNA appeared to be most common in the examination room, especially on fomite sites in direct contact with koalas. Physical removal of chlamydial DNA, or its degradation by the elements, appeared to be more common on outdoor enclosures, clothing, and hands. Based on the cell culture assay, of the pre-decontamination samples with chlamydial DNA, eight had viable chlamydial cells, two of these at low levels. Of the post-decontamination samples with chlamydial DNA, one had a moderate number, and one had a very low number of viable chlamydial cells. RT-qPCR was unsuccessful in determining cell viability due to low yields of RNA and high levels of contaminants from the environmental samples. The outcomes of this study provide a knowledge base for the design of future biosecurity evaluation guidelines in captive and koala rehabilitation facilities. The higher incidence of chlamydial DNA detection by qPCR than viable organism highlights the need to use viability assays in similar studies. However, further investment is still needed to optimise these methods and improve sensitivity for complex environmental samples.
在野外捕捉或康复环境中，考拉之间的传播是一个潜在的风险，因为考拉被近距离关押在一起，或者设备在动物之间共享。鉴于衣原体对考拉福利和种群生存能力的影响，令人惊讶的是，考拉康复设施或捕捉环境中的检疫和消毒方案以前没有得到评估。本研究旨在评估一种方法，该方法基于检测衣原体 DNA 和细胞活力，以确定考拉护理设施内环境污染物的程度。在澳大利亚新南威尔士州的一个考拉康复设施中，与考拉护理相关的各种污染物被确定为衣原体污染的潜在来源，这些污染物接触了已知感染的考拉。在暴露后和进行去污程序后，对污染物进行了拭子取样。使用 qPCR 检测样品中是否存在衣原体 DNA，使用 RT-qPCR 和细胞培养检测样品的活力。在总共 239 次采样事件中，有 30 次 qPCR 检测到衣原体 DNA 呈阳性，其中 19 次和 11 次分别对应于预去污和后去污事件。在检查室中，尤其是在与考拉直接接触的污染物上，检测到衣原体 DNA 的情况最为常见。在户外围栏、衣物和手上，衣原体 DNA 的物理去除或被元素降解似乎更为常见。基于细胞培养检测，在有衣原体 DNA 的预去污样本中，有 8 个样本有活的衣原体细胞，其中 2 个样本的活细胞数量较低。在有衣原体 DNA 的后去污样本中，有 1 个样本有中等数量的活细胞，有 1 个样本有非常低数量的活细胞。由于环境样本中 RNA 产量低和污染物水平高，RT-qPCR 未能确定细胞活力。本研究的结果为设计未来圈养和考拉康复设施的生物安全评估指南提供了知识基础。qPCR 检测到的衣原体 DNA 发生率高于活生物体，这突出表明需要在类似研究中使用活力测定法。然而，仍需要进一步投资来优化这些方法，并提高复杂环境样本的敏感性。
