Laboratory of Wildlife Comparative Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
Institute for Animal Health and Food Safety, School of Veterinary Medicine, University of Las Palmas of Gran Canaria, Arucas, Gran Canaria, Spain.
PLoS One. 2019 Mar 20;14(3):e0213363. doi: 10.1371/journal.pone.0213363. eCollection 2019.
Cetacean morbillivirus (CeMV) is a major natural cause of morbidity and mortality in cetaceans worldwide and results in epidemic and endemic fatalities. The pathogenesis of CeMV has not been fully elucidated, and questions remain regarding tissue tropism and the mechanisms of immunosuppression. We compared the histopathologic and viral immunohistochemical features in molecularly confirmed CeMV-infected Guiana dolphins (Sotalia guianensis) from the Southwestern Atlantic (Brazil) and striped dolphins (Stenella coeruleoalba) and bottlenose dolphins (Tursiops truncatus) from the Northeast-Central Atlantic (Canary Islands, Spain) and the Western Mediterranean Sea (Italy). Major emphasis was placed on the central nervous system (CNS), including neuroanatomical distribution of lesions, and the lymphoid system and lung were also examined. Eleven Guiana dolphins, 13 striped dolphins, and 3 bottlenose dolphins were selected by defined criteria. CeMV infections showed a remarkable neurotropism in striped dolphins and bottlenose dolphins, while this was a rare feature in CeMV-infected Guiana dolphins. Neuroanatomical distribution of lesions in dolphins stranded in the Canary Islands revealed a consistent involvement of the cerebrum, thalamus, and cerebellum, followed by caudal brainstem and spinal cord. In most cases, Guiana dolphins had more severe lung lesions. The lymphoid system was involved in all three species, with consistent lymphoid depletion. Multinucleate giant cells/syncytia and characteristic viral inclusion bodies were variably observed in these organs. Overall, there was widespread lymphohistiocytic, epithelial, and neuronal/neuroglial viral antigen immunolabeling with some individual, host species, and CeMV strain differences. Preexisting and opportunistic infections were common, particularly endoparasitism, followed by bacterial, fungal, and viral infections. These results contribute to understanding CeMV infections in susceptible cetacean hosts in relation to factors such as CeMV strains and geographic locations, thereby establishing the basis for future neuro- and immunopathological comparative investigations.
鲸类麻疹病毒（CeMV）是世界范围内鲸类发病率和死亡率的主要自然原因，导致流行和地方性致命。CeMV 的发病机制尚未完全阐明，关于组织嗜性和免疫抑制机制仍存在疑问。我们比较了分子确认的西南大西洋（巴西）的瓜纳亚那宽吻海豚（Sotalia guianensis）和东北-中大西洋（加那利群岛，西班牙）的条纹海豚（Stenella coeruleoalba）和宽吻海豚（Tursiops truncatus）以及西地中海（意大利）感染 CeMV 的瓜纳亚那宽吻海豚的组织病理学和病毒免疫组织化学特征。重点放在中枢神经系统（CNS）上，包括病变的神经解剖分布，还检查了淋巴系统和肺。根据定义的标准选择了 11 只瓜纳亚那宽吻海豚，13 只条纹海豚和 3 只宽吻海豚。条纹海豚和宽吻海豚的 CeMV 感染表现出明显的嗜神经性，而瓜纳亚那宽吻海豚的 CeMV 感染则很少见。加那利群岛搁浅海豚的神经解剖病变分布显示大脑、丘脑和小脑一致受累，随后是尾部脑干和脊髓。在大多数情况下，瓜纳亚那宽吻海豚的肺部病变更严重。淋巴系统在这三个物种中均受累，表现为一致的淋巴耗竭。多核巨细胞/合胞体和特征性的病毒包涵体在这些器官中也有不同程度的观察。总体而言，广泛存在淋巴组织细胞、上皮细胞和神经元/神经胶质病毒抗原免疫标记，存在一些个体、宿主物种和 CeMV 株的差异。同时存在机会性感染，尤其是内寄生虫感染，其次是细菌、真菌和病毒感染。这些结果有助于了解易感鲸类宿主中的 CeMV 感染与 CeMV 株和地理位置等因素的关系，从而为未来的神经和免疫病理学比较研究奠定基础。
