7株H3亚型禽流感病毒HA基因的遗传演化分析

Genetic variation analysis of HA genes of seven strains of avian influenza virus subtype H3

采用RT—PCR技术对近年来洞庭湖区分离的H3亚型禽流感毒株的HA基因进行扩增、克隆和测序，并对所得全序列进行同源性和遗传演化分析。结果显示：本试验分离到的7株H3亚型禽流感病毒的HA裂解位点均没有多个连续的碱性氨基酸插入，属于低致病性病毒；7株H3亚型毒株之间HA基因核苷酸同源性在87．6％～98．4％之间，推导氨基酸序列的同源性在93．7％～99．1％之间；从HA基因遗传演化关系来看，7株病毒毒可分为三大分支，与以往从蒙古、韩国、越南、西伯利亚及我国香港、广西、三江等地分离的H3亚型毒株关系密切，提示其HA基因来源非常复杂。

In order to explore the genetic variation and evolution of avian influenza virus （AIV） subtype H3 isolated from Dong Ting lake area, and to provide a basis about prevention and control of avian influenza subtype H3 in the region, seven strains of AIV subtype H3 were isolated from Dong Ting lake area and the whole HA cDNA fragments of these strains were amplified and sequenced. The HA gene analysis and genetic evolution results showed that 7 strains belonged to low pathogenic avian influenza virus. The HA gene nucleotide homology shared 87.6% to 98.4% among 7 strains, while the derived amino acid sequence homology were 93.7% to 99. 1%. Phylogenetic results showed that the isolates could be divided into three branches, and the relations were closer to some strains isolated from Mongolia, Korea, Vietnam, Siberia and HongKong, Guangxi and Sanjiang, which indicated that the source of HA gene was very complicated.