Analysis Result on Etiological Surveillance of Influenza in Tianshui from 2017 to 2024

Wang Yuanchun; Wang Yu; Shi Xiuqing; Zhao Jingyi

doi:10.3969/j.issn.1001-568X.2025.08.0011

Abstract：OBJECTIVE To analyze the etiological characteristics of influenza in Tianshui of Gansu from 2017 to 2024,and provide theoretical basis for influenza prevention and control.METHODS Real-time fluorescent PCR technology was used to conduct nucleic acid testing on 12 401 throat swab specimens from influenza-like cases submitted by two sentinel hospitals in Tianshui from 2017 to 2024.Descriptive epidemiological methods were employed to analyze the test results.RESULTS A total of 12 401 throat swab specimens from influenza-like cases were tested,with 1 124 positive specimens detected,giving a total positive rate of 9.06％.The positive rate was the highest in 2019(23.04％)and the lowest in 2020(1.7％).The differences in positive rates among different years were statistically significant(x2=575.269,P＜0.05),and the composition ratios of dominant strains varied.Each subtype showed an alternating epidemic pattern.There were statistically significant differences in positive rates among different months(x2=833.977,P＜0.05).Except for 2020 to 2022,there were two epidemic peaks each year.The main epidemic peak occurred from January to April,mainly caused by the H1N1 subtype of influenza A.The secondary peak occurred from November to December,mainly caused by the H3N2 subtype of influenza A.In terms of age distribution,there were statistically significant differences in positive detection rates(x2=138.757,P＜0.05).The positive detection rate was the highest in the 15～25 age group,mainly caused by the H3N2 subtype of influenza A.The positive detection rates were the lowest in the 0～5 and ≥60 age groups,mainly caused by the H1N1 subtype of influenza A.CONCLUSION Types,predominant strain and positive rate of influenza virus present dynamic changes in different years,months and ages from 2017 to 2024,and predominant influenza virus alternately prevail,and the incidence of influenza present seasonal characteristics.So it is necessary to strengthen etiological surveillance of influenza to timely grasp predominant strain change and incidence trend of influenza.