Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to es...Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to estimate the population attack rate and its variations, the consultation rates, hospitallization and mortality rates. Methodology: A representative random sample of the population of a commune in Chile (San Felipe) was interviewed and taken blood samples between January and March 2010. A study against the antibodies of the influenza A(H1N1) pdm09 virus was conducted, by the technique of the Hemaglutination Inhibition (HAI) according to standardized methodology. Subjects with antibody titers ≥1:40 were considered positive. Results: 13.5% of the population of San Felipe had antibodies against influenza A(H1N1)pdm09;this percentage reached 30% of the population between 0 and 18 years and 6.1% among those over 19 years. The age variable was the only factor that evidenced significant differences in the prevalence of antibodies. There were no significant differences related to gender, vaccination history against seasonal inluenza, or comorbidity. 51% of people with positive serology showed IN-FLUENZA-LIKE SYMPTOMS. Conclusions: A relevant percentage of subclinical disease was detected in the first pandemic wave in Chile and the proportion of people with SARI and deaths was small. Data from epidemiological surveillance were useful to estimate the trend of TSI but not its magnitude.展开更多
【目的】了解浙江省湖州市2023年A(H1N1) pdm09流感流行株耐药基因变异和遗传进化特征。【方法】收集2家流感监测医院的呼吸道标本进行A(H1N1) pdm09流感病毒核酸检测,阳性标本接种MDCK细胞进行流感病毒分离和测序。应用DNA Star 7.1软...【目的】了解浙江省湖州市2023年A(H1N1) pdm09流感流行株耐药基因变异和遗传进化特征。【方法】收集2家流感监测医院的呼吸道标本进行A(H1N1) pdm09流感病毒核酸检测,阳性标本接种MDCK细胞进行流感病毒分离和测序。应用DNA Star 7.1软件和Mega4.0软件对神经氨酸酶(NA)基因酶活性位点和M2离子通道蛋白(M2蛋白)与耐药相关的氨基酸位点进行分析。【结果】分离株与疫苗株的NA基因核苷酸同源性范围为98.87%~99.22%,氨基酸同源性范围为98.94%~99.36%。M基因核苷酸同源性范围为99.07%~99.85%,氨基酸同源性范围为99.02%~99.94%,分离株和疫苗株同属于6B.1A.5a.2a进化分支。NA基因酶活性中心关键位点氨基酸仍高度保守,与NA抑制剂耐药相关的9个关键氨基酸位点无变异,但部分流行株非酶活性位点发生一些变异。分离株M2蛋白与耐药相关的5个氨基酸位点未发生替换,但第31位氨基酸由丝氨酸变为天冬酰胺。【结论】2023年湖州市A(H1N1) pdm09流行株与世界卫生组织(WHO)推荐的2023—2024年疫苗株有较高的同源性。所有流行株均对金刚烷胺类药物耐药。展开更多
文摘Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to estimate the population attack rate and its variations, the consultation rates, hospitallization and mortality rates. Methodology: A representative random sample of the population of a commune in Chile (San Felipe) was interviewed and taken blood samples between January and March 2010. A study against the antibodies of the influenza A(H1N1) pdm09 virus was conducted, by the technique of the Hemaglutination Inhibition (HAI) according to standardized methodology. Subjects with antibody titers ≥1:40 were considered positive. Results: 13.5% of the population of San Felipe had antibodies against influenza A(H1N1)pdm09;this percentage reached 30% of the population between 0 and 18 years and 6.1% among those over 19 years. The age variable was the only factor that evidenced significant differences in the prevalence of antibodies. There were no significant differences related to gender, vaccination history against seasonal inluenza, or comorbidity. 51% of people with positive serology showed IN-FLUENZA-LIKE SYMPTOMS. Conclusions: A relevant percentage of subclinical disease was detected in the first pandemic wave in Chile and the proportion of people with SARI and deaths was small. Data from epidemiological surveillance were useful to estimate the trend of TSI but not its magnitude.