2019-2020年甘肃省外环境禽流感病毒及职业暴露人群血清学分析

Serological surveillance for avian influenza virus in environment and population with occupational exposure in Gansu,2019–2020

目的了解2019—2020年甘肃省职业暴露人群禽流感病毒接触感染状况及活禽市场外环境中禽流感病毒的分布,为防控禽流感疫情提供科学依据。方法采集活禽市场笼具表面擦拭物及粪便等环境标本,采用实时荧光RT-PCR法检测标本中甲型通用流感病毒核酸,阳性标本再检测H5、H7和H9亚型禽流感病毒核酸。同时采集禽流感职业暴露人群血清标本,采用红细胞凝集抑制实验法检测禽流感病毒H5N6、H7N9、H9N2抗体。结果共采集外环境标本5225份,检出甲型通用(FluA)阳性1069份,总阳性率为20.46%;流行株为H9型,存在14份H7和H9混合感染;各地区阳性率差异较大,前5位分别为定西市(40.79%)、天水市(40.00%)、陇南市(37.63%)、白银市(31.05%)和嘉峪关市(26.35%);禽流感病毒阳性率以宰杀或摆放禽肉案板表面的擦拭标本最高(46.26%)、禽类饮水最低(15.71%),差异有统计学意义(χ^(2)=21.038,P<0.05),437份职业暴露人群血清标本中检出7份H9抗体阳性。结论甘肃省涉禽外环境中存在的禽流感病毒污染主要为H9亚型,零星检出H7亚型,未检出H5亚型,职业暴露人群中存在少量H9N2隐性感染,应加强主动监测以防止禽流感暴发流行。

Objective To understand the infection status of avian influenza virus in population with occupational exposure s in Gansu province from 2019 to 2020 and the contamination of avian influenza viruses in the environment of live poultry markets,and provide evidence for the prevention and control of human infection with avian influenza virus.Methods Environmental samples such as surface swabs of poultry cages and feces of poultry,were collected from live poultry markets in Gansu.Realtime fluorescent RT-PCR was used to detect nucleic acid of influenza A virus in the samples.The positive samples were then tested for nucleic acid of H5,H7 and H9 subtypes of avian influenza virus.At the same time,serum samples from population with occupational exposure to avian influenza virus were collected,and the hemagglutination inhibition(HI)method was used to detect the antibodies to avian influenza A(H5N6),A(H7N9),and A(H9N2)viruses.Results A total of 5225 environmental samples were collected from 2019 to 2020,in which 1069 were positive(20.46%);the predominant strains belong to subtype H9,and there were 14 mixed infections of subtype H7 and H9 viruses;the positive rate in Dingxi was highest(40.79%),followed by Tianshui(40.00%),Longnan(37.63%),Baiyin(31.05%)and Jiayuguan(26.35%).The positive rate of avian influenza virus was highest(46.16%)in poultry chopping board swabs(46.26%)and lowest in poultry drinking water samples(15.71%).The difference was significant(χ^(2)=21.038,P<0.05).Seven serum H9 antibody positive samples were detected in 437 persons with occupational exposures.Conclusion Avian influenza virus contamination in the environment of live poultry markets in Gansu was mainly caused by subtype H9 virus,subtype H7 was sporadically detected,and no subtype H5 virus was detected,and there was less latent H9N2 virus infection in the population with occupational exposures.Active surveillance should be strengthened to prevent the outbreak of human infection with avian influenza virus.