| Objective:This study analyzed the data of influenza-like illness reported by the hospitals at the influenza surveillance outpost and the data of pathogen detection in the laboratory of the influenza surveillance network in Jilin province from 2010 to 2018,to understand the prevalence of influence and the distribution of influenza virus in Jilin province.In addition,the meteorological data of Changchun City were analyzed to understand the meteorological factors related to influenza-like illness,and provide a data support for the prediction of the impact of meteorological factor fluctuations on influenza dynamics.Methods:In this study,the influenza surveillance data of Jilin province from 2010 to 2018 came from "China influenza surveillance information system",and the meteorological data of Changchun City from 2010 to 2017 came from "China meteorological data network".Excel software was used to establish database,and SPSS24.0 and R3.6.1 software were used for data analysis.Descriptive statistical analysis of influenza surveillance results was carried out and the relationship between meteorological factors and the risk of influenza-like illness was analyzed using a generalized additive model based on poisson distribution.Results:1.A total of 315,508 influenza-like illness in the national influenza surveillance post hospitals were reported and the outpatient and emergency cases in the post hospitals totaled 17,554,797 in Jilin province from 2010 to 2018,the influenza-like illness ratio(ILI %)was 1.80%.The ILI% was highest in 2014 and lowest in 2010,at 3.04% and 1.10%,respectively.2.From 2010 to 2018,Jilin province saw a peak of ILI % from November to April each year,presenting a seasonal trend.The composition of influenza-like illness was as follows: 35.51% in people aged 0 to 5,28.26% in people aged 5 to 15,10.43% in people aged 15 to 25,21.27% in in people aged 25 to 60,and 4.54% in people aged over 60.Among the regions in Jilin province,Siping City had the highest ILI %(3.42%),and Songyuan City had the lowest ILI %(0.91%).3.A total of 65,602 ILI specimens were collect from Jilin provincial national influenza surveillance outpost hospital from 2010 to 2018,of which 64,601 were tested,with a detection rate of 98.47%.A total of 8,278 positive specimens were detected,with a positive rate of 12.81%.Among the positive specimens,the A(H3N2)subtype was the most,with a total of 3505 cases,followed by 1767 cases of the A(H1N1)subtype and 1244 cases of the B(Yamagata)subtype.One H7N9 infections were reported in Changchun City in 2014.4.From 2010 to 2018,Jilin province saw a peak of positive rate of influenza virus from November to April each year.The highest positive rate was found at 2010,with a positive rate of 17.91%.The positive rate of the two adjacent years shows a trend of alternating high and low.The dominant strains of influenza were also different in two adjacent years and in the early and late stage of an influenza epidemic.The highest positive rate was 15.02% in the 5-15 age group,followed by 13.95% in the 15-25 age group and 13.44% in the over-60 age group.The lowest positive rate was 11.15% in the 0-5 age group.Among the cities in Jilin province,Baishan City had the highest positive rate of influenza virus(15.99%),followed by Changchun City(14.75%)and Jilin City(14.19%).Liaoyuan City had the lowest positive rate of influenza virus(5.21%).5.The dominant strain in Jilin province was type B in the epidemic period of 2010 and 2011-2012.The dominant strain during the influenza epidemic period from 2013 to 2014 was A(H1N1).During the influenza epidemic period from 2014 to 2015,the dominant strain was seasonal A(H3N2).The dominant strain in the early stage of the influenza epidemic period from 2015 to 2016 was seasonal A(H3N2),and in the later stage was B(Victoria).The dominant strain during the epidemic period of 2017-2018 was B(Yamagata)type.The dominant strains of influenza virus were the same in all age groups,all of which were seasonal A(H3N2).The dominant strains of influenza virus were also consistent in all regions.6.A total of 165,538 influenza-like illness were reported at the national influenza surveillance post hospital in Changchun City from 2010 to 2017,with an average of 49 cases reported daily.During the same period,the average daily temperature in Changchun City was 5.7℃,the average daily relative humidity was 64.7%,the average daily wind speed was 2.8 m/s,and the average daily sunshine duration were 6.8 h.7.In the general population,the relative risk of average temperature on ILI is the lowest when lagging for 0 and 1 day,which is 0.90(95%CI: 0.85~0.96)and 0.90(95%CI: 0.84~0.95),respectively.When the cumulative lag days were 7 days,the relative risk of the impact of average temperature on ILI was the lowest,which was 0.81(95%CI: 0.74~0.89).When the cumulative lag days were 3 days and 4 days,the relative risk of the influence of the two-day temperature difference on ILI was the lowest,which was 0.96(95%CI: 0.93~0.99).The relative risk of average relative humidity on ILI was the lowest When lagging for 7 days,which was 0.96(95%CI: 0.94~0.99).8.The influence of meteorological factors on the incidence of ILI is different in different age groups.For example,in the population of 5-15 years old and over 60 years old,the influence of average daily temperature on the incidence of ILI was not statistically significant,but it was statistically significant in the total population and other age groups.In the age group of 5-15 years old,the influence of the two-day temperature difference on the incidence of ILI was statistically significant.The relative risk was 0.94(95%CI: 0.90~0.98)when lagging for 0 day,but the influence was not statistically significant in other age groups.The influence of precipitation on the incidence of ILI in the 5-15 age group was statistically significant,and the relative risk was 0.90(95%CI: 0.84~0.97)when the cumulative lag days were 6 days,but the correlation was not statistically significant in other age groups.Conclusions:1.The influenza epidemic in Jilin province occurs from November to April of each year,showing a seasonal characteristics of winter and spring.2.The number of ILI medical treatment and ILI % in Jilin province showed an increasing trend,and the population aged from 0 to 15 years old was the high-risk group of ILI.3.Influenza viruses circulating in Jilin province are type A and type B,among which A(H3N2)is the main virus threatening the health of residents in Jilin province.4.The dominant strains of influenza virus in different cities of Jilin province were the same,but the dominant strains of influenza virus in different years were different.5.The positive rate of influenza virus in different populations was different,among which the positive rate was the highest in people aged 5 to 15,and the positive rate of was the lowest in people aged 0 to 5.6.The risk of H7N9 infection among residents of Changchun City remains.7.Temperature,relative humidity and rainfall are related to the occurrence of ILI,and the effects of meteorological factors on ILI in different populations are also different. |
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