Ma Dongmei, Deng Guocheng, Bai Junjie, Li Shengjie, Yu Lingyun, Quan Yingchun, Yang Xiaojing, Jiang Xiaoyan, Zhu Zemin, Ye Xing
a Ministry of Agriculture of the People's Republic of China Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute , Chinese Academy of Fishery Sciences , Guangzhou , 510380 , China.
J Aquat Anim Health. 2013 Sep;25(3):197-204. doi: 10.1080/08997659.2013.799613.
In April 2011, 40% mortality of Largemouth Bass Micropterus salmoides juveniles occurred at a farm of Zhongshan City, Guangdong Province, China. Infected fish became lethargic, exhibited corkscrew and irregular swimming, and developed a distended abdomen and crooked body. Fish began to die within 2 d after the appearance of clinical signs. In order to analyze the pathogeny and diagnose the disease earlier, observation of clinical signs, cell infection, titer calculation, electron microscopy, immersion infection assay for fish, and nucleotide sequence analysis were carried out. Fathead minnow (FHM) cell cultures, inoculated with filtrate of liver and spleen homogenates from the diseased fish, developed the obvious cytopathic effect 46 h after inoculation in the primary culture and 24 h at the first passage. Typical rhabdovirus particles, 115-143 nm in length and 62-78 nm in diameter, were observed in infected FHM cells by direct transmission electron microscopy. The isolated virus produced a titer of 10(7.15) TCID50/mL. Immersion-Fish infected with the virus had similar clinical signs and 80% mortality with 10(2.5) LD50/mL. The data indicated that the rhabdovirus was the lethal pathogeny of the current disease. Based on nucleoprotein-gene nucleotide sequence multiple alignment analysis, the newly isolated virus is a strain of Siniperca chuatsi rhabdovirus (SCRV) under family Rhabdoviridae, which was initially isolated from Mandarin Fish Siniperca chuatsi. Up to the present, at least four virus strains have been isolated from diseased Largemouth Bass, which have had different clinical signs. Comparison of the clinical signs can help in an early diagnosis of the disease.
2011年4月，中国广东省中山市某养殖场的大口黑鲈幼鱼死亡率达40%。患病鱼变得行动迟缓，出现螺旋式和不规则游动，腹部肿胀且身体弯曲。鱼在出现临床症状后2天内开始死亡。为分析病因并尽早诊断疾病，进行了临床症状观察、细胞感染、滴度计算、电子显微镜检查、鱼的浸泡感染试验及核苷酸序列分析。用患病鱼肝脏和脾脏匀浆滤液接种的黑头呆鱼（FHM）细胞培养物，在原代培养接种后46小时和首次传代后24小时出现明显细胞病变效应。通过直接透射电子显微镜在感染的FHM细胞中观察到典型的弹状病毒粒子，长度为115 - 143纳米，直径为62 - 78纳米。分离出的病毒产生的滴度为10(7.15) TCID50/mL。用该病毒浸泡感染的鱼出现类似临床症状，10(2.5) LD50/mL时死亡率达80%。数据表明弹状病毒是当前疾病的致死病原体。基于核蛋白基因核苷酸序列多重比对分析，新分离的病毒是弹状病毒科下的鳜鱼弹状病毒（SCRV）毒株（最初从鳜鱼分离得到）。截至目前，至少已从患病大口黑鲈中分离出四种病毒毒株，它们具有不同的临床症状。临床症状的比较有助于疾病的早期诊断。
