Chapman Phoebe A, Owen Helen, Flint Mark, Soares Magalhães Ricardo J, Traub Rebecca J, Cribb Thomas H, Kyaw-Tanner Myat T, Mills Paul C
Veterinary-Marine Animal Research, Teaching and Investigation, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Veterinary-Marine Animal Research, Teaching and Investigation, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia; School of Forest Resources and Conservation, University of Florida, The Florida Aquarium's Center for Conservation, Apollo Beach, FL, USA.
Int J Parasitol Parasites Wildl. 2017 Mar 1;6(1):39-47. doi: 10.1016/j.ijppaw.2017.03.001. eCollection 2017 Apr.
Spirorchiid blood fluke infections affect endangered turtle populations globally, and are reported as a common cause of mortality in Queensland green sea turtles. Both the flukes and their ova are pathogenic and can contribute to the stranding or death of their host. Of particular interest are ova-associated brain lesions, which have been associated with host neurological deficits. Accurate estimations of disease frequency and the relative effect of infection relating to different spirorchiid species are made difficult by challenges in morphological identification of adults of some genera, and a lack of species-level identifying features for ova. A new specifically designed molecular assay was used to detect and identify cryptic spirorchiids and their ova in Queensland green sea turtle tissues collected from 2011 to 2014 in order to investigate epidemiology, tissue tropisms and pathology. Eight spirorchiid genotypes were detected in 14 distinct tissues, including multiple tissues for each. We found no evidence of a characteristic pathway of the eggs to the exterior; instead the results suggest that a high proportion of eggs become lost in dead-end tissues. The most common lesions observed were granulomas affecting most organs with varying severity, followed by arteritis and thrombi in the great vessels. The number of spirorchiid types detected increased with the presence and severity of granulomatous lesions. However, compared with other organs the brain showed relatively low levels of spirorchiid diversity. An inverse relationship between host age and spirorchiid diversity was evident for the liver and kidneys, but no such relationship was evident for other organs. Molecular data in this study, the first of its kind, provides the first species-level examination of spirorchiid ova and associated pathology, and paves the way for the future development of targeted ante-mortem diagnosis of spirorchiidiasis.
旋睾科血吸虫感染影响着全球濒危海龟种群，据报道，它是昆士兰绿海龟死亡的常见原因。吸虫及其虫卵均具有致病性，可导致宿主搁浅或死亡。特别值得关注的是与虫卵相关的脑部病变，这些病变与宿主的神经功能缺损有关。由于某些属的成虫在形态学鉴定上存在挑战，且虫卵缺乏物种水平的鉴别特征，因此难以准确估计疾病发生率以及不同旋睾科物种感染的相对影响。为了调查流行病学、组织嗜性和病理学，我们使用了一种新设计的分子检测方法，来检测和鉴定2011年至2014年采集的昆士兰绿海龟组织中的隐匿旋睾科吸虫及其虫卵。在14种不同组织中检测到了8种旋睾科基因型，每个组织都检测到了多种基因型。我们没有发现虫卵排出体外的特征途径的证据；相反，结果表明，很大一部分虫卵在盲端组织中丢失。观察到的最常见病变是影响大多数器官的肉芽肿，严重程度各不相同，其次是大血管中的动脉炎和血栓。检测到的旋睾科类型数量随着肉芽肿病变的出现和严重程度而增加。然而，与其他器官相比，大脑中的旋睾科多样性水平相对较低。肝脏和肾脏中宿主年龄与旋睾科多样性之间存在明显的负相关，但其他器官中没有这种关系。本研究中的分子数据是同类研究中的首个数据，首次对旋睾科虫卵及相关病理学进行了物种水平的研究，为未来旋睾科病的靶向生前诊断的发展铺平了道路。
