Surveillance of avian influenza virus in external environment in Jieyang, Guangdong, 2016-2020

Abstract

Objective To understand the dynamic distribution and epidemic characteristics of avian influenza virus in external environment in Jieyang, assess the risk of human infection with avian influenza, and we provide scientific basis for prevention and control of human avian influenza. Methods According to the random sampling method, relevant specimens were collected from poultry markets in 5 counties (county-level cities and districts) in Jieyang, 2016-2020. Real-time fluorescence quantitative RT-PCR method was used to detect the nucleic acid of influenza virus Type A. Positive specimens were then tested for the nucleic acid of H5N6, H7N9 and H9N2 subtypes of avian influenza virus. Results From 2016 to 2020, a total of 1 798 environmental samples were collected, of which 660 samples were positive for influenza A virus (FluA), with a positive rate of 36.71%. The positive rates of H5N6, H7N9 and H9N2 subtypes were 1.61%, 1.28% and 21.91%, respectively. The positive rate of avian influenza virus was higher in Puning county-level city (54.14%) and Huilai county (51.43%), and lowest in Jiexi county (4.84%). The highest positive rate of different types of samples (47.09%) was the washing of poultry sewage. Conclusion There are H5N6, H7N9, H9N2 and various subtypes of avian influenza virus contamination in external environment of poultry markets in Jieyang. The avian influenza virus has a wide epidemic area and there is a risk of human infection. It is necessary to continue to strengthen the real-time monitoring of avian influenza in external environment and the health supervision of urban and rural poultry market. 摘要：目的 了解揭阳市外环境禽流感病毒动态分布情况和流行特点, 评估人感染禽流感病毒的风险, 为人禽流 感防控提供科学依据。 方法 按随机抽样的方法, 对揭阳市2016—2020年5个县 (市、区)禽类市场进行相关标本采 集, 用实时荧光定量(RT-PCR)对标本进行流感病毒A型检测, 阳性标本再进行H5N6、H7N9、H9N2亚型禽流感病毒核 酸检测。 结果 揭阳市2016—2020年共采集外环境标本1 798份, 甲型流感病毒(FluA)阳性标本660份, 阳性率为 36.71%;其中H5N6、H7N9、H9N2亚型阳性率分别为1.61%、1.28%和21.91%。普宁市和惠来县的外环境禽流感病毒阳 性率较高, 分别为54.14%和51.43%。揭西县的外环境禽流感病毒阳性率最低, 为4.84%。不同类型标本检测阳性率最 高为清洗禽类污水(47.09%)。 结论 揭阳市禽类市场外环境中存在H5N6、H7N9、H9N2及多种亚型混合的禽流感病 毒污染, 禽流感病毒流行区域较广, 存在感染人的风险, 应继续加强外环境禽流感实时监测和城乡禽类市场卫生监管。