Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; Department of Zoology, Faculty of Science, Cairo University, Cairo, Egypt.
Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; Department of Zoology and Entomology, Faculty of Science, Helwan University, Helwan, Egypt.
Gene. 2019 Jan 30;683:243-252. doi: 10.1016/j.gene.2018.10.041. Epub 2018 Oct 17.
A total of 100 specimens of the greater lizardfish Saurida tumbil were collected during the current investigation from the coasts of Hurghada City at the Gulf of Suez, Red Sea, Egypt; and necropsied to study their metazoan parasites. Of the total specimens collected, 32.0% were found to be naturally infected with hemiurid trematodes. The prevalence of parasitic infections increased to 48.0% during winter and fell to 16.0% during summer season with no mixed infections being observed. Two species of the hemiurid trematodes were recovered from the stomach of the infected fish samples; both belonged to the genus, Lecithocladium, in the family Hemiuridae. The morphometrics of their different body parts were characterized by light microscopy. Comparisons between the recovered parasites and previously studied species showed that the present investigation is the first report of Lecithocladium species infecting marine fish in the Red Sea. Additionally, molecular analysis of the parasites' 18S small subunit (SSu) rDNA was performed to determine their phylogenetic position in relation to previously recorded species in GenBank, which distinctly supported the morphological characteristics identified here. Two hemiurid species from the genus, Lecithocladium, to be L. cristatum and L. parviovum, were identified. Comparison of 18S rDNA sequences revealed that they had 98.0% sequence identity with L. excisum (gb| AJ287529) with a low divergence value. On the basis of these results, the two species isolated here were recorded within a new host and locality records in Egypt.
本次调查共从埃及苏伊士湾赫尔格达市沿海采集了 100 个大蜥蜴鱼 Saurida tumbil 的标本，并对其进行了剖检，以研究其后生动物寄生虫。在所采集的总标本中，有 32.0%被发现自然感染了半尾科吸虫。寄生虫感染的流行率在冬季增加到 48.0%，在夏季下降到 16.0%，没有观察到混合感染。从感染鱼样本的胃中回收了两种半尾科吸虫；它们都属于半尾科的 Lecithocladium 属。通过光学显微镜对它们不同身体部位的形态特征进行了描述。与以前研究过的物种进行比较表明，本次调查是首次报道 Lecithocladium 物种感染红海的海洋鱼类。此外，还对寄生虫的 18S 小亚基（SSu）rDNA 进行了分子分析，以确定它们与 GenBank 中记录的以前物种的系统发育关系，这明显支持了这里确定的形态特征。从 Lecithocladium 属中鉴定出两种半尾科物种，即 L. cristatum 和 L. parviovum。18S rDNA 序列比较表明，它们与 L. excisum (gb| AJ287529) 的序列同一性为 98.0%，具有较低的分歧值。基于这些结果，这里分离出的两种物种在埃及的新宿主和新地点记录中被记录下来。
