福建省新型鸭呼肠孤病毒生物学特性及基因序列分析

Biological Characterization and Gene Sequence Analysis of a Novel Duck Reovirus in Fujian Province

为了解福建省新型鸭呼肠孤病毒(NDRV)生物学特性和遗传变异状况,从福建省番鸭主要饲养区采集了8份临床发病样品进行病原学检测、病原分离、攻毒试验及S1基因序列分析。结果显示:8份临床样品均为NDRV阳性,接种番鸭胚后均成功分离到病毒;将NDRV尿囊液毒感染番鸭后3~10 d发病,发病率为20%~40%,死亡率为0~20%,剖检可见肝脏有出血斑及大量白色坏死灶,脾脏肿大坏死,与参考毒株NDRV-NP03相比,部分分离毒株毒力有所下降。S1基因序列分析发现:NDRV分离毒株与省内毒株亲缘关系较近,与省外毒株亲缘关系相对较远;在系统进化树上,8株NDRV分离毒株聚为同一分支,而福建省外毒株聚为另一分支,说明NDRV呈区域性流行特征;σC蛋白氨基酸序列与NP03株相比,存在12个差异位点,可能会导致NDRV感染能力发生改变。

In order to identify the biological characteristics and genetic variation of a novel duck reovirus(NDRV)in Fujian Province,8 clinical samples were collected from Muscovy ducks in intensive farms in Fujian Province for pathogenic detection,pathogen isolation,challenge test and Sl gene sequence analysis.The results showed that all the 8 samples were positive for NDRV,and NDRV was isolated from Muscovy duck embryos inoculated with grinding fluid of samples;the ducks showed clinical symptoms in 3-10 d after being infected with NDRV allantoic fluid,with a morbidity rate of 20%-40%and a mortality rate of 0-20%,hemorrhage spots and numerous white necrotic foci were observed in livers under autopsy,the spleens were oedema,and compared to the reference strain NDRV-NP03,the virulence of some isolates decreased.SI gene sequence analysis showed that NDRV isolates were closer to the strains isolated within the same province,but more distant from others isolated in other provinces;8 NDRV isolates were clustered in the same branch in the phylogenetic tree,but others isolated outside of Fujian Province were in other branch,indicating regional epidemic of the NDRV;and compared to NP03 strain,12 differential sites were found in the amino acid sequence of oC protein,which might change the performance of NDRV infection.