Epidemic Characteristics And Etiology Surveillance Of Influenza From 2012 To 2017 In Urumqi

Objective: Through the surveillance of influenza-like cases and etiology in Urumqi 2012-2017,To understand the epidemic level,epidemic trend and etiology characteristics of influenza and to forecast the trend of cases of influenza-like illness,provide a scientific and effective basis for influenza prevention and control measures in Urumqi.Methods: In this study,descriptive epidemiological methods were used to analyze surveillance data of influenza like illness(ILI)at sentinel hospital in Urumqi during 2012-2017.The ARIMA model was used for time series analysis to predict the incidence of influenza-like cases.Real-time PCR method was used to detect nucleic acid in ILI specimens,and positive strains were detected by cell culture method to isolate influenza strains.Statistical analysis of the monitoring data was performed using SPSS 20.0 software.Results: 1.Distribution of influenza-like cases: 2012-2017 ILI% of Urumqi was 12.93%(167861/1298616).The difference of ILI% in five years was statistically significant,the age group was mainly 0-14 years old,and the peak of winter and spring season was obvious.2.Etiological monitoring: The positive rate of the test for pharyngeal swab specimens in influenza-like cases in 2012-2017 was 18.21%(1360/7470).Influenza virus type characteristics of each year: ?In addition to the influenza A virus epidemic in 2012-2013 alone,influenza A and B viruses were mixed in the remaining four years,and the H3N2 subtype influenza virus in type A was in the trend of the following year from 2012 to 2017.?Type A H3N2 subtype influenza virus non-dominant year,the type A and type B influenza-based mixed epidemic,and no obvious regular B-type influenza.Different factors(age group,source of specimen,sampling period and sampling time)showed statistically significant difference in isolation rate of strains.3.Outbreak monitoring: in 2012-2017,Urumqi reported 20 cases of influenza outbreak,with an average incidence rate of 1.53%.The time distribution is consistent with the monitoring time of influenza-like cases,mainly in winter and spring,mainly in primary and secondary schools,mainly in type B.4.The establishment of the ARIMA time series model shows that the simulation of the model during 2012-2017 is reasonable.Judging from the forecasted results,it will gradually increase in April-June 2017 and gradually decline after June.Conclusion: Most influenza in Urumqi is high in the winter and spring,and children aged 0-14 years are the main group of influenza cases.Therefore,influenza surveillance at primary and secondary schools should be strengthened during the high season of influenza,and preventive and control measures should be well implemented.Plant type vaccination with the corresponding vaccine to reduce the occurrence of influenza and the emergence of outbreaks.In addition,the predominant strains of influenza virus strains in each year showed alternate changes and caused influenza epidemics in varying degrees.In the future,the molecular biology of influenza virus should be strengthened,and new strains of influenza virus should be discovered.In addition,the use of ARIMA model can better simulate and predict the incidence of influenza-like illness in Urumqi,providing a certain reference for the prevention and control of influenza.