Wei Jingguang, Huang Youhua, Zhu Weibin, Li Chen, Huang Xiaohong, Qin Qiwei
Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, People's Republic of China.
Guangdong Winsun Bio-pharmaceutical Co., Ltd., Guangzhou, People's Republic of China.
Arch Virol. 2019 Jul;164(7):1869-1872. doi: 10.1007/s00705-019-04268-z. Epub 2019 May 9.
In recent years, with the rapid development of marine farming activities, outbreaks of viral diseases have affected the grouper aquaculture industry, causing heavy economic losses. Singapore grouper iridovirus (SGIV) is one of the most important viruses causing disease in fish. In the present study, we isolated and identified a virus from diseased groupers by coculturing the affected tissue cells with grouper spleen cells. The genome of the isolated virus shared 99.83% nucleotide sequence homology with those of SGIV reference strains in the GenBank database. The virus clustered with SGIV on an evolutionary tree constructed based on "major capsid protein" (MCP) amino acid sequences, so it was designated 'Singapore grouper iridovirus Hainan' (SGIV-HN). To evaluate the pathogenic potential of SGIV-HN in fish, orange-spotted groupers were infected by intraperitoneal injection with the virus. Infected groupers began to die from the fourth day after infection, and survivors tended to be stable by the eighth day. The death rate was 83.33%. In a mock-infected control group, only two fish died, and the mortality rate was 6.67%. Dissection showed that the fish had enlarged spleens with hemorrhage, and enlarged cells were visible with Giemsa staining. This is the first report of isolation of SGIV from naturally infected fish in China, and we show that SGIV-HN is highly infectious, causing massive deaths in groupers.
近年来，随着海水养殖活动的迅速发展，病毒性疾病的爆发影响了石斑鱼养殖业，造成了巨大的经济损失。新加坡石斑鱼虹彩病毒（SGIV）是导致鱼类发病的最重要病毒之一。在本研究中，我们通过将患病石斑鱼的组织细胞与石斑鱼脾脏细胞共培养，从患病石斑鱼中分离并鉴定出一种病毒。分离出的病毒基因组与GenBank数据库中SGIV参考毒株的核苷酸序列同源性为99.83%。在基于“主要衣壳蛋白”（MCP）氨基酸序列构建的进化树上，该病毒与SGIV聚类，因此被命名为“海南新加坡石斑鱼虹彩病毒”（SGIV-HN）。为了评估SGIV-HN对鱼类的致病潜力，通过腹腔注射该病毒感染点带石斑鱼。感染的石斑鱼在感染后第四天开始死亡，到第八天存活鱼趋于稳定。死亡率为83.33%。在 mock 感染对照组中，仅两条鱼死亡，死亡率为6.67%。解剖显示鱼的脾脏肿大并伴有出血，吉姆萨染色可见肿大的细胞。这是中国首次从自然感染的鱼类中分离出SGIV的报道，并且我们表明SGIV-HN具有高度传染性，可导致石斑鱼大量死亡。
