ABSTRACT: Bonamiosis has developed as a problem in Australian native oysters Ostrea angasi since the parasite Bonamia spp. was first detected in Port Phillip Bay, Victoria, in the early 1990s. At that time, large-scale mortalities in both farmed and wild oysters saw the demise of the pilot native oyster culture industry. More recent attempts to farm the species resulted in subclinical infections that progressed over time to clinical disease. The aim of this work was to establish what environmental factors result in the clinical manifestation of disease; determine the diagnostic sensitivity and diagnostic specificity of histopathological examination and a quantitative polymerase chain reaction (qPCR) test for the diagnosis of B. exitiosa infection in clinically diseased farmed native oysters; and calculate the optimal qPCR threshold cycle (C_T) epidemiological cut-point for classification of positive and negative cases. After applying a range of stressors to tank-held oysters, results indicated a 58% increased risk (95% CI: 16%, 99%) of a Bonamia-infected oyster dying if the oyster was held at a higher temperature (p = 0.048). Starving and tumbling oysters, in isolation, was not significantly associated with clinical bonamiosis, but a Bonamia-infected oyster was at the greatest risk of death when increased water temperature was combined with both starvation and increased motion (p = 0.02; odds ratio = 3.47). The diagnostic sensitivity and specificity of the World Organisation for Animal Health qPCR protocol were calculated for increasing C_T value cut-points from ≤25 to ≤40, with an optimal cut-point identified at ≤34.5 (specificity: 92.2; 95% posterior credible intervals [PCI]: 76.2, 99.8; Sensitivity: 93.5; 95% PCI: 84.7, 99.1).

中文翻译：

---

澳大利亚人工养殖的​​牡蛎Ostrea angasi中的exit鱼Bonamia exitiosa：最佳流行病学qPCR切入点和临床疾病危险因素。

摘要：自寄生虫Bonamia spp以来，澳大利亚本地牡蛎Ostrea angasi便已出现Bonamiosis问题。于1990年代初在维多利亚州的菲利普湾湾首次发现。当时，养殖牡蛎和野生牡蛎的大量死亡见证了当地牡蛎养殖试验产业的消亡。最近对该物种进行养殖的尝试导致了亚临床感染，这种感染随着时间的推移逐渐发展为临床疾病。这项工作的目的是确定什么环境因素导致疾病的临床表现。确定组织病理学检查的定量诊断敏感性和诊断特异性，以及定量聚合酶链反应（qPCR）检测对出口假单胞菌的诊断临床患病的养殖牡​​蛎感染；并计算最佳qPCR阈值周期（C _T）流行病学临界值，以对阳性和阴性病例进行分类。在将一系列压力物施加到罐装牡蛎上后，结果表明，如果将牡蛎置于较高温度下，则感染Bon鱼的风险会增加58％（95％CI：16％，99％）（p = 0.048） ）。孤立地，饥饿和翻滚的牡蛎与临床bonamiosis并没有显着相关，但是Bonamia当水温升高与饥饿和运动增加相结合时，感染牡蛎的死亡风险最高（p = 0.02；优势比= 3.47）。计算世界动物卫生组织qPCR协议的诊断敏感性和特异性，以将C _T值的切点从≤25增加到≤40，确定的最佳切点为≤34.5（特异性：92.2； 95％后可信间隔[PCI]：76.2、99.8；灵敏度：93.5； 95％PCI：84.7、99.1）。