山西亚群H5N1亚型HPAIV对鸭及鸭胚的继代感染研究  

Successive passages of H5N1 highly pathogenic avian influenza virus clade SX in ducks and duck embryos

作　　者：张翼[1] 段振华[1] 刘丽玲[1] 施建忠[1] 田国彬[1] 曾显营[1] 陈化兰[1] 李雁冰[1] 

机构地区：[1]中国农业科学院哈尔滨兽医研究所兽医生物技术国家重点实验室/农业部动物流感重点开放实验室/国家禽流感参考实验室,黑龙江哈尔滨150001

出　　处：《中国预防兽医学报》2010年第5期365-369,共5页Chinese Journal of Preventive Veterinary Medicine

基　　金：国家"十一五"科技支撑计划(2006BAD06A03);农业部动物流感防治与监测专项

摘　　要：2006年从山西省分离获得的H5N1亚型禽流感病毒(AIV)曾引起免疫鸡群的大量死亡,与我国之前分离的病毒抗原差异性较大,称为"山西鸡型"抗原变异株。本研究应用该亚群代表毒株CK/SX/2/06(H5N1),研究该病毒对SPF鸭和鸭胚的致病性,并通过病毒在鸭和鸭胚内的连续传代,探讨该亚群病毒在鸭和鸭胚中的进化规律。结果表明,病毒对3周龄鸭呈低致病性,在各脏器中的复制能力较弱;鸭感染病毒后无明显临床症状,排毒水平较低并且不能感染同居鸭。病毒在3周龄鸭和10日龄鸭胚中分别继代感染3代和5代后,对3周龄鸭仍呈低致病性且HA基因未发生氨基酸位点变化。病毒不能致死3周龄鸭和1日龄雏鸭,但能致死10日龄～23日龄鸭胚,而且对鸭胚的致病性随着鸭胚日龄的增长逐渐减弱,致死鸭胚时间从对10日龄鸭胚24h致死到对23日龄鸭胚72h致死直至对25日龄鸭胚只感染但不致死。病毒对鸭呈低致病性且在鸭群传播中保持着基因水平和致病性上的相对稳定,对不同日龄鸭胚、1日龄和3周龄鸭致病性的不同表现,与目前存在于我国的其他亚群H5N1HPAIV对鸭致病性和进化特点上呈现出明显的差异,并对家禽养殖业存在威胁。The H5N1 highly pathogenic avian influenza viruses（HPAIV） prevailing in Shanxi and Ningxia provinces formed the Shanxi Clade（Clade SX）,and were shown antigenically drifted from the other HPAIV previously isolated in China.In this study,pathogenicity index of a representaive strain HPAIV CK/SX/2/06（H5N1） was analyzed in ducks and duck embryos by successive passages.The results showed that the virus had low pathogenicity to the 3-week-old SPF ducks with no clinic symptoms and low virus titres in tissues.The pathogenicity reminded similar after 3 passages in ducks and 5 passages in duck embryos.Sequence analysis showed that no amino acid changes occurred in HA genes between viruses of different passage.The virus was lethal to 10 to 23 day duck embryos,but pathogenicity of the virus decreased accordingly with the duck embryos growing,with all 25-day-old duck eggs survived post inoculation.Viruses of the Clade SX presented low pathogenicity to ducks and remained conservative in amino acid sequence,showing significant difference with other clades of virus and posting a pandemic threat to poultry.

关 键 词：禽流感病毒 山西亚群 鸭 鸭胚 继代感染 

分 类 号：S852.659.5[农业科学—基础兽医学]