Department of Parasitology, Faculty of Veterinary Medicine, Cairo University, Egypt.
Department of Aquatic Animal Medicine and Management, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
Microb Pathog. 2022 Dec;173(Pt A):105867. doi: 10.1016/j.micpath.2022.105867. Epub 2022 Nov 2.
Dactylogyrus extensus and Pseudomonas fluorescens are serious pathogens in Cyprinus carpio aquaculture causing severe impacts and substantial economic losses. During the early spring of 2021, abnormal mortalities were reported among farmed C. carpio. Moribund fish showed anorexia, respiratory distress, dermal ulcers, and septicemia. The water analysis revealed low dissolved oxygen (3.4 mg/L), and high un-ionized ammonia levels (0.65 mg/L). Seventy moribund C. carpio specimens were collected and subjected to parasitological and bacteriological examinations. The monogenetic trematode D. extensus was discovered in wet mounts from the gills of all the examined fish samples (100%). The identity of recovered parasites was confirmed by sequencing and alignment of the 28S rDNA gene. P. fluorescens was concurrently identified in the infested fish samples (58.5%) based on phenotypic characteristics using the API20 E. The identity of bacterial isolates was confirmed further by sequencing and alignment of 16S rRNA gene. The IL-1β and MHCII were upregulated in infested fish in tandem with the severity of infections. P. fluorescens isolates displayed high resistance to most of the tested antibiotics. The study is one of the earlier reports on D. extensus and P. fluorescens co-infections in farmed C. carpio and highlights the need of effective control programs to protect fish health and minimize losses.
过度伸展的指环虫和荧光假单胞菌是鲤鱼养殖中的严重病原体，对鲤鱼养殖造成严重影响和重大经济损失。2021 年初春，报告了养殖鲤鱼的异常死亡率。濒死的鱼表现出食欲不振、呼吸困难、皮肤溃疡和败血症。水质分析显示溶解氧低（3.4mg/L），非离子氨水平高（0.65mg/L）。收集了 70 条濒死的鲤鱼标本，并进行了寄生虫学和细菌学检查。在所有检查的鱼样本的鳃部湿载片中发现了单殖吸虫过度伸展的指环虫（100%）。回收寄生虫的身份通过测序和 28S rDNA 基因的比对得到确认。根据 API20E 对受感染鱼类样本的表型特征，同时鉴定出荧光假单胞菌（58.5%）。细菌分离物的身份通过 16S rRNA 基因的测序和比对进一步得到确认。在受感染的鱼类中，IL-1β 和 MHCII 与感染的严重程度一起上调。荧光假单胞菌分离株对大多数测试的抗生素表现出高耐药性。本研究是关于养殖鲤鱼中过度伸展的指环虫和荧光假单胞菌共同感染的早期报告之一，强调需要制定有效的控制计划，以保护鱼类健康并将损失降至最低。
