2017-2018年甘肃省外环境禽流感病毒监测分析

Analysis of avian influenza viruses surveillance results in the external environment in Gansu Province from 2017 to 2018

目的了解2017-2018年甘肃省活禽市场外环境中禽流感病毒的分布情况,为禽流感疫情防控提供科学依据。方法采集全省14个市(州)的活禽批发市场、城乡农贸市场或菜市场、家禽规模养殖场(户)和家禽散养户等禽流感监测点的笼具表面擦拭物、粪便等环境样本,采用实时荧光RT-PCR法检测样本中甲型流感病毒核酸(FluA),阳性样本再检测H5、H7和H9亚型禽流感病毒核酸。结果共采集外环境样本7038份,检出FluA核酸阳性1510份,总阳性率为21.45%。H5、H7和H9亚型禽流感病毒核酸的阳性率依次为0.06%(4/7038)、1.19%(84/7038)和20.52%(1444/7038)。共检出H5、H9混合感染样本2份,H7、H9混合感染样本20份。不同类型样本中FluA核酸阳性率差异有统计学意义(χ^(2)=50.232,P<0.01),宰杀或摆放禽肉案板表面的擦拭样本阳性率最高(36.04%),禽类饮水样本阳性率最低(13.27%)。FluA阳性率在2018年1月最高(36.64%),2017年6月最低(5.60%)。定西市FluA核酸阳性率最高(63.32%)。结论2017—2018年甘肃省涉禽外环境中存在禽流感病毒污染,主要为H9亚型,同时检出H7和H5亚型,混合型占一定比例,需持续加强主动监测,防止禽流感暴发流行。

Objective To understand the distribution of avian influenza viruses in the environment of live poultry markets in Gansu Province from 2017 to 2018,so as to provide scientific basis for the prevention and control of avian influenza epidemic.Methods Environmental samples,including swabs of the surface and feces,were collected from the cages in live poultry wholesale markets,urban and rural farmers'markets,poultry farms(households)and poultry free-range households in 14 cities(prefectures)of Gansu Province,and undergone real-time fluorescence RT-PCR for detection of influenza A virus nucleic acid(FluA).The positive samples were further detected for H5,H7 and H9 subtypes of avian influenza virus nucleic acids.Results Totally,7038 samples were collected from the external environment,in which 1510 samples were identified positive for FluA,with a total positive rate being 21.45%.The positive rate for subtype H5,H7 and H9 was 0.06%(4/7038),1.19%(84/7038)and 20.52%(1444/7038),respectively.Mixed H5 and H9,and H7 and H9 infection was respectively detected in 2 and 20 samples.The positive rate for FluA was different in diverse samples(χ^(2)=50.232,P<0.01).The highest positive rate(36.04%)was found in swabs of the chopping boards for killing or treating the poultry,and the lowest(13.27%)in the water samples for feeding the poultry.FluA detection rate was the highest in January 2018(36.64%),and the lowest in June 2017(5.60%).The detection rate of FluA was the highest in Dingxi City(63.32%).Conclusion The environmental sites in Gansu Province from 2017 to 2018 was contaminated by avian influenza virus,with subtype H9 being dominant.Subtypes H7 and H5 as well as mixed infection were also detected in our samples,which suggests that strengthened active monitoring is necessary in following work.