External environment monitoring of avian influenza and serological analysis of occupational exposed population in Nanchong City from 2018 to 2022
Objective To understand the distribution of avian influenza virus(AIV)in the external environment of Nanchong City and the current status of AIV infection among occupational exposed populations,and to provide technical support for future prediction,early warning,and prevention and control of human avian influenza in Nanchong City.Methods From October 2018 to December 2022,some urban and rural live poultry markets,large-scale poultry farms,free range breeders and slaughterhouses in 9 counties/cities/districts of Nanchong City were selected as monitoring objects.Smear samples of the surface of cages,smear samples of the killing or placing poultry cutting boards,feces,cleaning poultry wastewater,poultry drinking water and other samples were collected.Real time PT-PCR(polymerase chain reaction)method was used to detect the FluA nucleic acid of avian influenza virus,and positive samples were further classified into H5,H7 and H9 subtypes by real-time fluorescence quantification.From 2019 to 2022,serum samples were collected from individuals engaged in poultry breeding,slaughtering and sales in January each year.Hemagglutination inhibition experiments were performed to detect serum antibodies against H9N2,H7N9 and H5N1.Excel 2022 and SPSS 26.0 software were used to organize data and statistical analysis.Chi-square test was used to compare the rates,and P＜0.05 was considered to be statistically significant.Results From 2018 to 2022,a total of 606 samples of avian influenza of external environment were collected in Nanchong City,of which 194 were positive for avian influenza virus,with a positive rate of 32.02％(194/606),mainly H9(54.12％,105/194).The positive rates were the highest in Gaoping District and Yingshan County(both 41.67％).There were significant differences in the positive rate among different years,seasons,places and sample types(x2=10.18,8.93,89.91,63.65,all P＜0.05).The highest positive rates were found in 2021(38.79％),in the fourth quarter(42.83％),in urban and rural live poultry markets(48.12％),and on the surface of killing or placing poultry cutting boards(56.72％).All of the 80 serum samples from the occupational exposed population were negative.Conclusions From 2018 to 2022,all relevant external environments in Nanchong City were exposed to avian influenza virus,mainly H9 subtype.The positive detection rate in urban and rural live poultry markets was higher.There is a risk of human infection with avian influenza.The next step should continue to carry out pathogen monitoring in key areas and strengthen health education for high-risk populations.
avian influenzaexternal environmentoccupational exposed population
NETL
NSTL
万方数据
