Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China.
Institute of Infectology, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 17493 Greifswald, Germany.
Viruses. 2021 Apr 30;13(5):807. doi: 10.3390/v13050807.
The hemorrhagic disease of grass carp (HDGC) caused by grass carp reovirus (GCRV) still poses a great threat to the grass carp industry. Isolation and identification of the GCRV genotype I (GCRV-I) has been rarely reported in the past decade. In this study, a new GCRV was isolated from diseased fish with severe symptoms of enteritis and mild hemorrhages on the body surface. The isolate was further identified by cell culture, transmission electron, indirect immunofluorescence, and SDS-PAGE electrophoretic pattern analysis of genomic RNA. The results were consistent with the new isolate as a GCRV-I member and tentatively named GCRV-GZ1208. Both grass carp and rare minnow infected by the GCRV-GZ1208 have no obvious hemorrhagic symptoms, and the final mortality rate was ≤10%, indicating that it may be a low virulent isolate. GZ1208 possessed highest genomic homology to 873/GCHV (GCRV-I) and golden shiner reovirus (GSRV). Additionally, it was found a 90.7-98.3% nucleotide identity, a 96.4-100% amino acid identity, and <50% identity with GCRV-II and III genotypes. Interestingly, the sequences of some segments of GZ1208 were similar to GCRV-8733/GCHV, whereas the remaining segments were more closely related to GSRV, suggesting that a recombination event had occurred. Bootscan analysis of the complete genomic sequence confirmed this hypothesis, and recombination events between 873/GCHV and other GSRV-like viruses were also accompanied by gene mutations.
草鱼出血病（HDGC）由草鱼呼肠孤病毒（GCRV）引起，仍对草鱼养殖业构成巨大威胁。在过去的十年中，很少有关于 GCRV 基因型 I（GCRV-I）的分离和鉴定的报道。在本研究中，从患有肠炎且体表有轻度出血的严重症状的患病草鱼中分离到了一种新的 GCRV。通过细胞培养、透射电镜、间接免疫荧光和基因组 RNA 的 SDS-PAGE 电泳图谱分析对分离株进行了进一步鉴定。结果与新分离株为 GCRV-I 成员一致，并暂定名为 GCRV-GZ1208。草鱼和稀有鲫感染 GCRV-GZ1208 后均无明显出血症状，最终死亡率≤10%，表明其可能是一种低毒力分离株。GZ1208 与 873/GCHV（GCRV-I）和金黄锦鲤呼肠孤病毒（GSRV）具有最高的基因组同源性。此外，它与 GCRV-II 和 III 基因型的核苷酸同一性为 90.7-98.3%，氨基酸同一性为 96.4-100%，同一性小于 50%。有趣的是，GZ1208 的一些片段的序列与 GCRV-8733/GCHV 相似，而其余片段与 GSRV 更为相似，表明发生了重组事件。完整基因组序列的 Bootscan 分析证实了这一假设，并且 873/GCHV 与其他 GSRV 样病毒之间的重组事件也伴随着基因突变。
