一起甲型H1N1流感暴发疫情的流行病学和病原学分析

The epidemiologic and virological analysis of an outbreak of influenza A/H1N1

目的 了解淮安市某中学甲型H1N1流感暴发的分子流行病学特征,为甲型H1N1流感疫情的控制提供依据.方法 采用现场流行病学方法,对甲型H1N1流感疫情进行调查分析;对病例标本进行病毒分离;采用巢式PCR扩增甲型H1N1流感病毒HA1基因的核苷酸序列,利用MEGA5.0分析软件,进行同源性分析和构建系统进化树.结果 疫情持续11天共确诊甲型H1N1流感样病例51例,罹患率为2.49％ （51/2051）.序列进化分析表明,本次疫情的病毒基因与2014年和2013年甲型H1N1流感病毒HA1基因核苷酸序列的同源性为分别为99.6％ - 99.9％和98.5％-98.8％,与2011年之前分离的核苷酸同源性为98.4％.结论 此次疫情流行程度较低,及时隔离病人及密切接触者在控制疫情中起到了重要作用;病毒基因变异程度不高,加强健康教育和疫苗接种有助于预防流感.

Objective To study the epidemiological characters of an influenza A/H1N1 outbreak in a middle school in Huaian city,and to provide scientific measures for prevention and control of influenza A/ H1N1.Method The outbreak of influenza A/H1N1 was investigated through the field epidemiology.The samples were used for virus isolation.Nucleotide sequences of H1N1 HA1 region were determined by RT-nested-PCR and sequencing.H1N1 genotypes were analyzed using bioinformatic programs by MEGA 5.0 software,and phylogenetic tree was constructed.Result 51 cases were reported during 11 days,the attack rate was 2.49% （51/2051）.The sequence analysis showed that the sequence homologous rates of H1N1 virus HA gene nucleotide were 99.6%-99.9% with H1N1 genotype in 2014,98.5%-98.8% in 2013,and lower than 98.4% in 2011.Conclusion The popularity of this outbreak was low.Timely isolation of H1N1 patients and close contacts played an important role in control the epidemics.Implementation of health propaganda and immunization of influenza A/H1N1 should be strengthened.