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目的了解2007-2011年深圳地区一般人群抗流感病毒H3N2抗体水平,H3N2亚型的HA、NA基因变异,观察人群感染流感病毒H3N2亚型动态变化。方法提取全区31个流感监测哨点的门诊急诊病例监测流感样病例(ILI),采用荧光定量PCR进行核酸检测,分离H3N2核酸阳性样本。随机选取H3N2病毒毒株进行HA、NA序列检测,用BioEdit和Mega5.0软件对HA、NA基因序列进行比对和分析。采用红细胞凝集抑制实验(HAI)检测人群抗H3N2血凝素(HA)抗原的抗体水平。结果深圳地区2007-2011年流感样病例占门诊急诊病例的百分率(ILI%)分别为6.66%、5.91%、7.06%、5.43%、4.69%;流感样病例中H3N2亚型核酸阳性率分别为6.9%、1.5%、9.3%、1.0%、0.8%。2007年与标准株A/Brisbane/10/2007的HA和NA同源性最高,依次逐年降低。82株主要氨基酸变异位点有2008年HA基因的A区位S140N/R,B区位K189E/N/Q,D区位E174K;2009-2011年B区位的N160K、K189Q,E区位E78K。人群抗HA抗原抗体2007与2011年抗体阳性率分别为69.4%、64.5%,差异无统计学意义。2008和2009年人群抗体分别为40.4%和38.4%,差异无统计学意义,但与2007或2011年的人群抗体阳性率两两比较差异有统计学意义(P<0.05)。结论 H3N2的HA、NA与当年的标准疫苗株同源性最高,依次逐年降低。2008和2009年HA基因有5个抗原决定簇位点高度变异,人群较低的抗体水平与2008-2009年H3N2病毒亚型高度流行相关。
Objective To understand the levels of anti-influenza virus H3N2 antibody and HA and NA of H3N2 subtype in the general population from 2007 to 2011 in Shenzhen, and to observe the dynamic changes of influenza virus H3N2 subtype in humans. Methods Thirty-one outpatient emergency surveillance samples were collected from 31 flu surveillance sentinel sites in the district. Fluorescent quantitative PCR was used to detect the nucleic acid, and H3N2 positive samples were isolated. HA and NA sequences were randomly selected from H3N2 virus strains. The sequences of HA and NA genes were aligned and analyzed by using BioEdit and Mega5.0 software. Antibody levels of anti-H3N2 hemagglutinin (HA) antigens were tested using the hemagglutination inhibition assay (HAI). Results The percentage of outpatient emergency cases in 2007-2011 in Shenzhen was 6.66%, 5.91%, 7.06%, 5.43% and 4.69%, respectively. The positive rates of H3N2 subtypes in influenza-like cases were 6.9 %, 1.5%, 9.3%, 1.0%, 0.8%. In 2007, the homology with HA and NA of standard strain A / Brisbane / 10/2007 was the highest, followed by decreasing year by year. The main amino acid variation sites of 82 strains were S140N / R of A region of HA gene in 2008, K189E / N / Q of B region and E174K of D region, and E78K of N160K, K189Q and E region of B region in 2009-2011. The positive rate of antibody against HA antigen in 2007 and 2011 was 69.4% and 64.5%, respectively, with no significant difference. The population antibody in 2008 and 2009 were 40.4% and 38.4%, respectively, with no significant difference. However, the antibody positive rate in 2007 and 2011 was statistically significant (P <0.05). Conclusion HA and NA of H3N2 have the highest homology with the standard vaccine strains of the current year, and successively decrease year by year. In 2008 and 2009, there were 5 epitopes of HA gene with high variation. The lower antibody level in the population correlated with the high prevalence of H3N2 virus subtype in 2008-2009.