沈阳市2005～2009年度冬春流感样病例病原学监测情况分析

Analysis of aetiological surveillance of influenza-like cases in epidemic seasons in Shenyang from 2005 to 2009

目的：分析沈阳市流感病毒的流行特点及其优势株的情况。方法：采集2005年~2009年冬春流行季哨点医院的流感样病例咽拭子,以MDCK细胞进行流感病毒的分离,根据CPE和HA方法鉴定流感病毒的存在,阳性毒株以HI和RT-PCR方法进行分型鉴定。结果：2005~2009年四个监测周期共采集流感样病例咽拭子样本783份,分离到流感病毒161株,总分离率为20.6%。其中A1型（H1N1）62株（38.5%）、A3型（H3N2）71株（44.1%）、B型（Yamagata系和Vic-toria系）28株（17.4%）。3种型别的毒株在5~岁和15~岁年龄组分离率最高（34.9%,31.7%）,但A3亚型在0~组所占比例最高（46.5%）。11月~次年1月为我市流感流行的冬高峰。结论：近年沈阳地区同时存在3种型别流感毒株流行,每年优势株明显不同,前一年监测周期的优势株在下一个周期中可被其他型别抑制甚至取代,2009~2010年监测周期中应密切关注A3（H3N2）亚型和SWH1N1亚型流感毒株的活动情况,加强学校人群的监测,及时发现流感病毒新变异株。

Objective：To analyze epidemic characteristic of influenza virus and its dominant strains.Methods：Throat swab samples of influenza-like cases were collected from sentinel hospitals in winter-to-spring epidemic seasons from 2005 to 2009,and influenza virus were isolated by MDCK cells,and its existence was proved by cytopathic effect（CPE） and hem agglutination（HA） tests,and positive strains were identified and typed by hem agglutination inhibition（HI） and real-time polymerase chain reaction（RT-PCR）.Results：783 throat swab samples were totally collected during 4 surveillance cycles from 2005~2009,161 influenza virus strains were isolated from them with total isolation rate 20.6%.Among these strains,there were 62 A1（H1N1） subtype（38.5%）,71 A3（H3N2） subtype（44.1%）,28 B（Yamagata series and Victoria series）（17.4%）.The isolation rate of 3 subtypes was the highest in 5~ and 15~ age groups（34.9%,31.7%）,but in 0~ age group,the proportion of A3 subtype was the highest（46.5%）.The winter peak of influenza epidemic in Shenyang occurred from November to January in the next year.Conclusion：In recent years,there coexisted epidemic of 3 subtypes of influenza virus strains and there were dominant strains each year significantly.The dominant strain of this surveillance cycle were inhibited or replaced by other subtypes.A3（H3N2） and SWH1N1 subtypes should be paid attention to during the surveillance cycle from 2009 to 2010,and surveillance in school should be strengthened to find new variant strains of influenza virus in time.