一株基因Ⅱ型鹅星状病毒的分离鉴定及培养特性

Isolation,Identification,and Culture characteristics of a GenotypeⅡGoose Astrovirus

【目的】明确鹅星状病毒(Goose astrovirus,GAstV)的致病性和体外培养特性。【方法】对广东某鹅场表现为内脏和关节痛风的发病鹅组织样品进行病原学检测、病毒分离鉴定、病毒基因序列测定与分析、病毒培养特性及致病性研究。【结果】从中分离到1株鹅星状病毒,命名为GD2208株;ORF2基因核苷酸序列比对分析显示,该毒株与基因Ⅱ型鹅星状病毒(GAstV-Ⅱ)参考株同源性最高,为97.4%~99.1%;进化树分析显示该毒株与GAstV-Ⅱ参考株处于同一进化分支。动物回归试验显示,以该毒株感染3日龄雏鹅后致死率为20%,感染鹅临床症状、剖检病变及病理组织学变化与自然发病鹅相似。禽胚及细胞适应性研究结果显示,该毒株能在鹅胚中稳定增殖,但盲传4代后仍无法适应SPF鸡胚和番鸭胚;病毒在GEK和LMH细胞中均能稳定增殖且可见明显细胞病变,在DF-1上可稳定繁殖,但盲传至8代后仍未见细胞病变。【结论】本研究自表现痛风症状雏鹅中分离到1株GAstV-Ⅱ毒株,该毒株感染3日龄雏鹅可发生典型痛风症状,对鹅胚、GEK、LMH和DF-1细胞均有一定适应性,以上结果为进一步开展GAstV的致病机制、疫苗和药物研发奠定了基础。

【Objective】To clarify the pathogenicity and culture characteristics of Goose astrovirus(GAstV).【Methods】Disease diagnosis and pathogen isolation,identification,gene sequencing,culture characteristics,and pathogenicity on a goose at a farm in Guangdong showing visceral and gout symptoms were conducted.【Results】The Goose astrovirus(GAstV)isolated from the tissue sample was named GD2208.It showed the highest homology of 97.4%–99.1%with the reference strain GAstV-Ⅱbased on the ORF2 gene nucleotide sequence.They belonged to the same evolutionary branch on the evolutionary tree.In an animal regression test,the chicks inoculated with GD2208 displayed similar clinical symptoms as well as the pathological and histopathological changes observed on the naturally infected 3-day-old goose and had a 20%mortality rate.The isolate could proliferate in goose embryos,but unable to adapt to SPF chicken or Muscovy duck embryos after 4 generations of blind transmission.It could also grow in GEK and LMH cells with the apparent cytopathic effects or in DF-1 cells without the effects after 8 generations of blind transmission.【Conclusion】A GAstV-Ⅱstrain isolated from a diseased goose when inoculated in healthy chicks produced similar symptoms on the birds,and it could grow in goose embryos,GEK,LMH,and DF-1 cells.