Abdel-Gaber Rewaida, Alajmi Reem, Quraishy Saleh Al, Morsy Kareem, Rasheid Khaled Al
Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia; Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt.
Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
Acta Trop. 2018 Jul;183:153-161. doi: 10.1016/j.actatropica.2018.04.016. Epub 2018 Apr 12.
Proteocephalids are cestoda parasites that mostly infect freshwater fish. The present study was carried out to investigate the presence of proteocephalids infecting the electric catfish Malapterurus electricus from Lake Manzala, Kafr El-Sheikh Governorate, Egypt. Morphological characterization revealed the present parasite is a cestoda belonging to the genus Electrotaenia. Morphologically, the recovered worms were characterized by an elongated body measuring 100-127 (120 ± 2) mm long and 0.92-2.11 (2.76 ± 0.1) mm wide. The anterior part of the worm was obvious terminated at a spherical scolex measured 1.12-1.91 (1.72 ± 0.01) mm long and 1.12-1.65 (1.42 ± 0.01) mm wide with a rostellum-like apical organ equipped by 5-6 irregular rows of minute hooklets, as well as four uniloculate suckers with a diameter of 0.13-0.15 (0.14 ± 0.01) mm and covered with microtriches. A long unsegmented neck was observed followed by acraspedote and anapolytic strobila consisted of 85-120 proglottids divided into 50-58 immature, 12-19 mature, and up to 49 gravid proglottids. Molecular characterization based on 28S rRNA sequences was done to confirm the taxonomy of this parasite based on its morphology. It was observed that there was a close identity up to 72.0% with other protocephalid species obtained for comparison from the GenBank. Also, the data obtained revealed that there was high blast scores and low divergence between the present parasite and previously described Electrotaenia malapteruri (acc. no. JX477434). Phylogenetic analysis showed that the parasite sequence in conjunction with existing data investigates the placement of this protocephalid species within Proteocephalidea. It was shown that the present species is deeply embedded in the genus Electrotaenia with close relationships to other Electrotaenia malapteruri as a putative sister taxon.
头槽绦虫是主要感染淡水鱼的绦虫寄生虫。本研究旨在调查埃及卡夫尔谢赫省曼扎拉湖的电鲶（Malapterurus electricus）体内是否存在感染的头槽绦虫。形态学特征表明，目前发现的寄生虫是一种属于电带绦虫属（Electrotaenia）的绦虫。从形态上看，回收的虫体特征为：虫体细长，长100 - 127（120 ± 2）毫米，宽0.92 - 2.11（2.76 ± 0.1）毫米。虫体前端明显终止于一个球形头节，头节长1.12 - 1.91（1.72 ± 0.01）毫米，宽1.12 - 1.65（1.42 ± 0.01）毫米，有一个类似顶突的顶端器官，配备5 - 6排不规则的微小钩，还有四个单腔吸盘，直径为0.13 - 0.15（0.14 ± 0.01）毫米，表面覆盖有微毛。观察到有一个长的不分节的颈部，接着是无节片和无节裂的链体，由85 - 120个节片组成，分为50 - 58个未成熟节片、12 - 19个成熟节片和多达49个妊娠节片。基于28S rRNA序列进行分子特征分析，以根据其形态确认该寄生虫的分类地位。结果发现，与从GenBank获取用于比较的其他头槽绦虫物种的相似度高达72.0%。此外，所获得的数据显示，目前的寄生虫与先前描述的电鲶电带绦虫（Electrotaenia malapteruri，登录号JX4***）之间有高的比对得分和低的差异度。系统发育分析表明，该寄生虫序列结合现有数据研究了这种头槽绦虫物种在头槽绦虫科（Proteocephalidea）中的位置。结果表明，目前的物种深深地嵌入电带绦虫属，与其他电鲶电带绦虫作为假定的姐妹分类单元关系密切。
