阿坝藏族羌族自治州流感哨点监测结果分析

Sentinel Surveillance of Influenza in Aba Tibetan and Qiang Autonomous Prefecture

目的分析2018-2019监测年度阿坝州流感监测结果,了解该年度流感病毒流行状况,分析型别分布特点,探讨流行规律,为阿坝州流感防控工作提供科学依据。方法通过"中国疾病预防控制信息系统"收集阿坝州流感样病例(ILI)监测资料,对其流行病学、病原学以及流感暴发疫情监测结果进行分析。采用狗肾传代细胞(MDCK)对流感病毒进行分离培养,并对分离到的流感毒株采用血凝抑制实验(HI)进行型别和亚型鉴定。采用单项血凝抑制试验,对分离到的流感毒株和标准株进行抗原性分析。结果 2018-2019监测年度阿坝州共采集流感样病例咽拭子1 286份,所有样本均按时进行核酸检测,检出流感病毒核酸阳性样本196份,总阳性率为15.24%。各个型别的阳性数分别为100份甲型H1N1,1份H3N2,95份B-Victoria系,分别占流感病毒核酸阳性数的51.02%、0.51%和48.47%,在整个监测年度并未检测出BYamagata系核酸阳性的样本。流感活动的明显高峰出现在2018年第40~43周、第51~52周,在2019年第1~3周有1个小高峰出现,前期以甲型H1NI为优势株,后期以B-Victoria系为优势株。本监测年度共分离流感毒株67株,分离率占流感病毒核酸阳性数的34.18%,其中55株甲型H1NI,B-Victoria系12株。结论 2018-2019监测年度阿坝州流感流行活动与流感病毒活动趋势比较一致,有明显的冬春季高峰,各型别流感病毒株的抗原性与标准株相比未发生明显变异。

Objective To analyze the annual influenza surveillance results of Aba Prefecture from 2018 to 2019,understand the epidemic situation and type distribution characteristics of influenza virus in this year and explore its epidemic trend,in order to provided scientific basis for influenza prevention and control in Aba Prefecture.Methods The Influenza-like Case(ILI)data in Aba Prefecture were collected from the China Disease Prevention and Control Information System and analyzed in epidemiology,etiology,and influenza outbreak surveillance results.The influenza virus were isolated and cultured by using dog kidney passage cells(MDCK).The isolated influenza strain was identified by hemagglutination inhibition test(HI)in type and subtype.Single-phase hemagglutination test was used to analyze the antigenicity of isolated influenza strains and standard strains.Results This study collected 1286 throat swabs from influenza-like cases from 2018-2019.All samples were tested for nucleic acid on time,and 196 positive samples of influenza virus nucleic acid were detected.The total positive rate was 15.24%.The positive numbers of each type were 100 samples of H1N1,1 of H3N2,and 95 samples of B-Victoria,which accounted for 51.02%,0.51%,and 48.47%of the positive number of influenza virus nucleic acids,respectively,and B-Yamagata was not detected throughout the year.The obvious peak of influenza activity occurred in the 40th week-43rd week,the 51st week-52nd week in 2018,and there was a small peak in 1st week-3rd week in 2019.A-type H1NI was dominated in the early stage and afterwards B-Victoria was the dominant strain.During 2018-2019,67 strains of influenza strains were isolated,and the isolation rate was accounted for 34.18%of the positive number of influenza virus nucleic acids,of which 55 strains were H1NI and 12 strains were B-Victoria.Conclusion During 2018-2019,the trend of influenza epidemic activities in Aba Prefecture was consistent with that of influenza viruses.It showed obvious peaks in winter and spring.Compared with the standard strains,the antigenicity of each type of influenza strains did not significantly change.