Research On Level Of Human Infection With Influenza A (H7N9) Virus In Zhejiang

Objective:1.Analyze the population distribution of disease,master the high risk population and acquire the infection feature about of human infection with novel influenza A(H7N9)virus in Zhejiang.2.According to the epidemiological information and pathogen detection,we will acquire the spectrum of infection of H7N9 among the mild and severe respiratory infection cases.3.Realize the H7 infections among the general population and occupational population in order to discover the H7N9 cases among healthy people in Zhejiang.4.Analyze the level of infection about above population,which provide scientific evidence for avian influenza prevention and control.Methods:1.Collect and analyze information about H7N9 cases up to June,2016 in Zhejiang so that we can know the epidemiologic feature of cases.Excel 2007 was used to enter and collate the data,SPSS 18.0 was used to analyze the data and ArgGIS was used to make maps.All statistical analysis followed the standard that P value of <0.05 was considered statistically significant.2.The blood samples which were derived from influenza-like illness(ILI)and severe acute respiratory infection(SARI)with poultry exposure history from 16 ILI sentinel hospital and 4 SARI sentinel hospital have been collected from 2013 to 2015.All samples were tested by nucleic acid testing.3.According to the sampling survey,the blood samples from general population and occupational population were collected.Samples were tested by hemagglutination inhibition test.1:80 or higher antibody titer tested was considered H7 positive.Results:1.Four waves occurred including 218 H7N9 cases with the high case fatality rates(39.4%)have been reported in Zhejiang up to June.The people with the age of 40 or more have occupied a large proportion among H7N9 cases and more likely to die(x2=21.899,P<0.001)in Zhejiang.Male patients more than female patients(1.8:1).Retirees and peasants account for 62.4%.The proportion of cases infected in city higher than those in country.However,the results have been reversed during fourth wave,and the difference of rural and urban distribution during four waves has statistically significant(x2=27.072,P<0.001).A large number of cases have one or more underlying disease and the H7N9 cases with underlying disease have higher mortality(x2=8.726,P=0.013).High blood pressure and diabetes were the most common diseases,prevalence rates have been reach up to 42.1% and 18.8% respectively.2.From 2013 to 2015,six H7 positive with 12/100000 positive rate and three H7 positive with 60/100000 positive rate have been found among ILI and SARI,respectively.Different years have no statistically significant among ILI and SARI(x2=2.091,P=0.343,x2=1.973,P=0.473)as well as different gender(P=0.687,P=0.275).Different age have different H7 positive rate among ILI and SARI(x2=12.334,P=0.001,x2=20.310,P<0.001).With age increasing,H7 positive rate was rising among ILI(x2=14.343,P=0.001).40~ and 60~ have higher H7 positive rate than other age group.3.28 H7 positive have been found among 3522 general population with 0.8% positive rate and 32 H7 positive have been found among 1559 occupational population with 2.1% positive rate.GMT was 1:5.2 and 1:6.8,respectively.The difference about antibody titer between general population and occupational population has statistically significant(x2=14.646,P<0.001),occupational population has higher antibody titer.Conclusions:1.The population of medium-elderly men,patients have underlying diseases,urban resident,retirees or peasants and patients with poultry exposure history prior to the onset of illness have occupied a larger proportion among H7N9 cases in Zhejiang.Medium-elderly men with underlying diseases have higher mortality.The proportion of including cases infected in country,have raise poultry history and have underlying diseases was increased gradually.2.A small number of H7 positive have been detected among ILI and SARI.Higher H7 positive rate were found among SARI than those among ILI.3.0.8% H7 positive rate was found among general population and 2.1% H7 positive rate was found among occupational population.Higher H7 positive rate were found among general population than those among occupational population.