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目的为了解在同一地区内同期发生的2起流行性感冒(流感)爆发中的病毒是否为同一性状以及病毒间抗原性的差异。方法从狗肾传代细胞(MDCK)分离的流感毒株提取病毒核糖核酸(RNA)后,经逆转录-聚合酶链反应(RT-PCR),扩增后的产物纯化后进行序列测定。结果2起爆发所分离的病毒经血清学鉴定均为甲3型流感病毒,核苷酸序列测定发现,引起2起爆发的甲3型流感病毒的抗原间有较大的差异。两者因10个核苷酸序列有差异而造成5个氨基酸被替换,其中3个发生在重要的抗原位点上,同源性98.5%。显示引起2起爆发的流感病毒并非来自同一毒株。其中1起爆发的毒株与2003年曾在宁波市流行的甲3型流感毒株同源性相接近,似是原先流行的毒株引起的爆发。而另1起爆发的毒株则与2003年流行的毒株同源性相差较远,并与当地后来流行的甲3型流感病毒的同源性更近,显然这是一起由流感病毒抗原性发生变异后的毒株引起的爆发。结论在同一地区同期流行的甲3型流感病毒的毒株并不一定为同一性状,抗原发生变异后的流感病毒可引起爆发,原先流行的毒株只要还有易感人群仍可造成爆发。
Objectives To understand whether the viruses in the two outbreaks of influenza (influenza) that occurred in the same area in the same area had the same trait and the difference in antigenicity between viruses. Methods RNA was isolated from influenza virus isolates from canine kidney cell line (MDCK). The amplified products were purified and sequenced by reverse transcription polymerase chain reaction (RT-PCR). Results The viruses isolated from the two outbreaks were serologically characterized as Influenza A (3) virus. The nucleotide sequence analysis showed that there were significant differences among the antigens of influenza A virus type 3 that caused two outbreaks. The difference between the 10 nucleotide sequences resulted in the substitution of 5 amino acids, of which 3 occurred at important antigenic sites with a homology of 98.5%. The flu viruses that caused the two outbreaks did not come from the same strain. One of the strains that broke out was similar to the homology of influenza A (3) strain that was endemic in Ningbo City in 2003, which seems to be caused by the original epidemic strain. While the other one outbreak of the strain with the 2003 epidemic strains of homology far apart, and later the local popular influenza virus type A homology closer, apparently this together by the influenza virus antigenic Variation of the strain caused by the outbreak. Conclusion The strains of Influenza virus type A (H3N1) circulating in the same area during the same period are not necessarily the same. Influenza virus after antigen mutation can cause outbreak, and the originally epidemic strains can still cause outbreak if there is still susceptible population.