四川地区养殖锦鲤浮肿病毒检测与系统进化分析

2017年10月,四川省某锦鲤养殖场暴发一种以嗜睡、腹部肿大、鳃肿胀和眼睛凹陷为临床特征的传染病,累计死亡率高达50%。为研究锦鲤发病病因和疾病流行规律,对病鱼解剖,进行病理组织观察、电镜观察、PCR检测和系统进化分析。结果显示,患病锦鲤眼球浑浊,腹部肿大,鳃肿胀严重;组织病理学观察发现病鱼的鳃、肝脏、肾脏和脑组织细胞变性、坏死,出现大量炎性细胞浸润;透射电镜观察,在肾脏组织中发现病毒粒子。巢氏PCR方法检测鲤浮肿病毒(carp edema virus,CEV),出现特异性扩增产物;基于CEV P4a基因进行系统发育分析,此病毒与英国株R083同源性为99%。本研究为鲤浮肿病毒的起源进化、分类、疾病诊断和防控提供重要依据。

Detection and phylogenetic analysis of carp edema virus (CEV) in farmed koi carp in Sichuan Province

In October 2017, an infectious disease broke out at a koi carp farm in Sichuan Province. It was characterized by drowsiness, abdominal swelling, gill swelling and eye depression. The cumulative mortality rate was 50%. In order to study its etiology and regularity of the disease, dissection, histopathology, electron microscopy and phylogenetic analysis were carried out. Principal symptoms included ocular opacity, abdominal swelling and gill necrosis. The gill, liver, kidney and brain tissues showed obvious degeneration, necrosis and massive inflammatory cell infiltration. Virus particles were found in kidney under transmission electron microscope. The specific amplification products of carp edema virus (CEV) were detected by nested-PCR. Based on CEV P4a gene, phylogenetic analysis showed that the homology between the isolated strain and British strain R083 was 90%. The result in this study was important for virus evolution, classification, viral diagonosis and disease control of carp edema virus.