Calero-Bernal R, Mauroo N F, Hui S W, Kuiken T, van de Bildt M W G, de Jong A W, Osterhaus A D M E, Sims L, Gendron-Fitzpatrick A, Carmena D, Cerqueira-Cézar C K, Rosenthal B M, Dubey J P
United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA.
Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region; Hong Kong Wildlife Health Foundation, G.P.O. Box 12585, Hong Kong Special Administrative Region.
Vet Parasitol. 2017 Feb 15;235:64-68. doi: 10.1016/j.vetpar.2017.01.001. Epub 2017 Jan 8.
Unlike most species in the genus Sarcocystis, Sarcocystis canis has a broad intermediate host range. Its life cycle is incompletely known and most reports are from the USA. Here we report fatal hepatitis in a 4year old male Indo-Pacific bottlenose dolphin (Tursiops aduncus) from Hong Kong associated with a S. canis-like infection. Diagnosis was made based on clinical presentation, histopathology, transmission electron microscopy (TEM), and molecular characterization. Microscopically, S. canis-like like infection was confined to the liver. Immature and mature schizonts were found in hepatocytes and the parasite was associated with generalized hepatic necrosis. By TEM, schizonts divided by endopolygeny, and merozoites lacked rhoptries. Molecular characterization of parasites present in liver and brain tissues at the cox1 gene showed a high degree of identity (97-98%) and clustered together with Sarcocystis canis, S. lutrae, S. arctica, S. speeri, S. turdusi, and S. rileyi in a phylogenetic study. This is the first report of S. canis-like infection from Asia.
与大多数肉孢子虫属物种不同，犬肉孢子虫具有广泛的中间宿主范围。其生命周期尚不完全清楚，大多数报告来自美国。在此，我们报告了一例来自香港的4岁雄性印太瓶鼻海豚（宽吻海豚）因疑似犬肉孢子虫感染而导致的致命性肝炎。诊断基于临床表现、组织病理学、透射电子显微镜（TEM）和分子特征。显微镜下，疑似犬肉孢子虫感染局限于肝脏。在肝细胞中发现了未成熟和成熟的裂殖体，并且该寄生虫与广泛性肝坏死有关。通过透射电子显微镜观察，裂殖体通过内多殖进行分裂，裂殖子缺乏棒状体。对肝脏和脑组织中存在的寄生虫的细胞色素c氧化酶亚基1（cox1）基因进行分子特征分析，结果显示高度同源（97 - 98%），并且在系统发育研究中与犬肉孢子虫、水獭肉孢子虫、北极肉孢子虫、斯氏肉孢子虫、椋鸟肉孢子虫和里氏肉孢子虫聚集在一起。这是亚洲首例疑似犬肉孢子虫感染的报告。
