2020年在湖北爆发了一种新出现的导致大规模死亡的养殖黄cat鱼(Pelteobagrusfulvidraco)疾病,中国。组织病理学检查表明患病鱼的肾脏和脾脏发生了显着变化。电子显微镜显示肾脏和脾脏中有大量病毒颗粒。这些颗粒是直径约35nm的球形。通过使用RNA测序和cDNA末端的快速鉴定,鉴定了病毒的完整核苷酸序列。病毒基因组包含7,432bp,包含三个开放阅读框,与其他病毒没有核苷酸序列相似性;然而,氨基酸序列与Picornavirales顺序中病毒的非结构(NS)蛋白的氨基酸序列部分匹配。结合系统发育分析,保守的氨基酸基序和病毒基因组的结构域预测典型的杯状病毒的基因组顺序。因此,该病毒暂定名为黄鲶鱼杯状病毒(YcCV)。细胞培养表明,YcCV可以在通道cat鱼肾细胞系(CCK)中引起早期传代的细胞病变作用。在人工感染中,这种病毒可以感染健康的黄鲶鱼,并导致类似于自然发生的临床症状。原位杂交分析检测到肾脏中病毒的阳性信号,脾,脾肝脏,心,和患病鱼类的ill组织。这项研究代表了黄cat鱼中杯状病毒感染的第一份报告,并为将来控制这种病毒性疾病的研究提供了坚实的基础。重要性杯状病毒是快速进化的病毒,其引起与全球显著的发病率和死亡率相关的大流行爆发。从黄鲶鱼中鉴定出的新型杯状病毒也会导致大量死亡。使用RNA测序(RNA-seq)和cDNA末端快速扩增(RACE)方法,鉴定和表征了完整的核苷酸序列,该病毒暂定名为黄鲶鱼杯状病毒(YcCV)。核苷酸序列相似性搜索发现与其他病毒没有匹配,和氨基酸序列比较表明与Picornavirales顺序的病毒具有约23.3%的氨基酸同源性。这些发现可能代表了解释病毒进化的新途径,并表明需要进一步研究杯状病毒的发病机理,并表征水产养殖环境中种间病毒之间可能的相互作用。
An emerging disease in farmed yellow catfish (Pelteobagrus fulvidraco) causing massive mortality broke out in 2020 in Hubei,
China. Histopathological examination indicated significant changes in kidneys and spleens of diseased fish. Electron microscopy revealed large numbers of viral particles in the kidneys and spleens. These particles were spherical with a diameter of approximately 35 nm. By using RNA sequencing and rapid identification of cDNA ends, the full nucleotide sequence of the virus was identified. The viral genome comprises 7,432 bp and contains three open reading frames sharing no nucleotide sequence similarity with other viruses; however, the amino acid sequence partially matched that of the nonstructural (NS) proteins from viruses in the order Picornavirales. Combined with the phylogenetic analysis, the conserved amino acid motifs and the domains of the viral genome predict a genome order typical of a calicivirus. Therefore, this virus was tentatively named yellow catfish calicivirus (YcCV). Cell culture showed that YcCV could cause a cytopathic effect in the channel catfish kidney cell line (CCK) at early passages. In artificial infection, this virus could infect healthy yellow catfish and led to clinical symptoms similar to those that occurred naturally. In situ hybridization analysis detected positive signals of the virus in kidney, spleen, liver, heart, and gill tissues of diseased fish. This study represents the first report of calicivirus infection in yellow catfish and provides a solid basis for future studies on the control of this viral disease. IMPORTANCE Caliciviruses are rapidly evolving viruses that cause pandemic outbreaks associated with significant morbidity and mortality globally. A novel calicivirus identified from yellow catfish also causes substantial mortality. Using an RNA sequencing (RNA-seq) and rapid amplification of cDNA ends (RACE) method, the full nucleotide sequence was identified and characterized, and this virus was tentatively named yellow catfish calicivirus (YcCV). A nucleotide sequence similarity search found no match with other viruses, and an amino acid sequence comparison indicated approximately 23.3% amino acid homology with the viruses in the order Picornavirales. These findings may represent a new avenue to explain virus evolution and suggest a need to further study the pathogenesis of calicivirus and characterize possible interactions among interspecific viruses in the aquaculture environment.