2019-2021年扬州市禽流感监测及职业暴露人群血清学分析

Surveillance of avian influenza virus and serological analysis of occupationally exposure population in Yangzhou City from 2019 to 2021

目的了解扬州市禽流感病毒(AIV)在外环境中的流行分布及职业暴露人群中暴露和感染情况,及时发现有公共卫生意义的AIV变异情况,为本地区禽流感疫情防控提供科学依据。方法采集禽类外环境标本、猪呼吸道标本及禽、猪职业暴露人群血清,利用实时荧光PCR技术对外环境标本及猪呼吸道标本进行FluA及H5、H7、H9、N1、N2、N6、N9亚型检测,HI实验检测血清标本中的H5、H7和H9禽流感抗体。结果禽相关外环境禽流感监测,2019—2021年共采集标本1196份,FluA、H5、H9、N1、N2及N6阳性率分别为12.29%(147/1196)、2.17%(18/1196)、11.62%(139/1196)、0.33%(4/1196)、11.79%(141/1196)及3.26%(39/1196),未检测出H7和N9亚型,两种及以上HA或NA亚型AIV同时检出共有35例,阳性率达2.93%(35/1196)。不同年份、场所、标本类型AIV阳性率比较差异均有统计学意义(χ^(2)=118.28、163.74、285.74,P<0.05)。AIV在2021年阳性检出率最高,达到30.63%(83/271);四类监测场所中,AIV在城乡活禽市场高发,检出率达到24.95%(126/505);六类标本类型中其他类型环境标本、宰杀或摆放禽肉案板表面的擦拭标本及清洗禽类的污水AIV阳性率超过50%。猪呼吸道标本监测,采集标本180份,未检测出AIV。禽与猪等职业暴露人群血清监测553份,未检测出H5、H7、H9禽流感抗体。结论扬州市外环境中AIV阳性率较高,型别多样,易发生基因重组,感染人的风险较高,应积极采取综合性防控措施,降低本地区外环境AIV阳性检出率,减少人感染风险。

Objective To investigate the distribution of avian influenza virus in the poultry related environment and the infection of avian influenza virus in population with occupational exposure to avian influenza virus,and provide evidence for the prevention and control of human avian influenza in this area.Methods The poultry related environment samples,the respiratory tract samples of pigs and the serum of population with occupational exposure to poultry and pigs were collected.Real time fluorescence quantitative PCR was used to detect the nucleic acid of influenza A virus in the poultry related environment samples and the respiratory tract samples of pigs.The positive samples were tested for nucleic of subtype H5,H7,H9,N1,N2,N6 and N9.The antibodies to influenza A(H5N6),(H7N9)and(H9N2)viruses in the serum of population with occupational exposure were detected by erythrocyte agglutination inhibition test(HI).Results Avian influenza surveillance in poultry⁃related external environment,a total of 1196 samples were collected from 2019 to 2021,and the positive rates of FluA,H5,H9,N1,N2 and N6 were 12.29%(147/1196),2.17%(18/1196),11.62%(139/1196),0.33%(4/1196),11.79%(141/1196)and 3.26%(39/1196),H7 and N9 subtypes were not detected.Two or more HA or NA subtypes of AIV were detected simultaneously in 35 cases,with a positive rate of 2.93%(35/1196).There were significant differences in the positive rate of AIV in different years,monitoring sites and sample types(χ^(2)=118.28,163.74,285.74,P<0.05).AIV has the highest positive detection rate in 2021,reaching 30.63%(83/271);among the four types of surveillance sites,AIV is highly prevalent in urban and rural live poultry markets,with a detection rate of 24.95%(126/505).Among the six types of samples,the AIV positive rate of other types of environmental samples,wiped specimens on the cutting board surface of slaughtered or placed poultry meat,and sewage from washing poultry exceeded 50%.No AIV positive was detected in 180 samples of porcine respiratory tract.553 samples of serum samples from occupationally exposed groups such as poultry and pigs were monitored,and no H5,H7,H9 avian influenza antibodies were detected.Conclusion The positive rate of avian influenza virus in poultry related environment in Yangzhou is high,the AIV types are diverse,the genetic recombination is prone to occur,and the risk of infecting people is high.Therefore,comprehensive prevention and control measures should be actively taken to reduce the positive detection rate of avian influenza in the external environment of the region and reduce human infection risk.