2017年江西省人感染H7N9禽流感疫情期间试点地区活禽市场病毒污染现况及干预效果分析

目的 了解2017年上饶市人感染H7N9禽流感疫情期间活禽市场禽流感污染状况，并评价采取休市、清洗消毒等措施后的卫生效果，为今后制定禽流感防控策略提供依据。方法 通过检测病例暴露溯源、活禽市场日常禽流感监测以及不同干预期采集的标本，分析外环境中禽流感病毒污染状况及卫生措施效果。结果 2017年上饶市活禽市场关闭后无新发病例；病例溯源活禽市场A型和H7型的阳性率均高于家禽散养户，差异均有统计学意义(χ2值分别为39.16、31.26，P＜0.05)；溯源活禽市场A型和H7型禽流感的阳性率均高于日常监测，差异均有统计学意义(χ2值分别为7.68、10.96，P＜0.05)；采取休市2周较休市1周和休市前，A型和H7型的阳性率呈明显下降，且休市1周和2周的风险值呈逐渐下降，其中A型 1周和2周的风险值分别为0.301(0.192～0.472)和0.077(0.048～0.142)，均有统计学意义(P＜0.05)，H7型在1周和2周的风险值分别为0.251(0.162～0.390)和0.021(0.008～0.055)，均有统计学意义(P＜0.05)；复市1周内A型和H7型阳性率均处于较低水平，未出现明显上升。结论 采取2周以上的休市措施能有效降低外环境中禽流感病毒污染和人群的暴露风险，全面关闭活禽市场对疫情的控制有十分的重要作用。

Analysis of avian influenza virus pollution status during the epidemic of human infection with avian influenza H7N9 and intervention effect in live poultry market of pilot area in 2017

Objective In order to understand the avian influenza virus pollution status in live poultry markets during the outbreak of avian influenza A(H7N9), and evaluate the sanitary effects after adopting market management measures such as market closing, cleaning and disinfection, and finally to provide evidence for bird flu prevention and control strategies for the future. Methods Through detecting the samples of case exposure tracing, daily avian influenza surveillance in the live poultry market and collected during different intervention periods, and analyzed the pollution status of avian influenza virus in the external environment and the effects of health measures. Results In 2017, no new cases were reported after the closure of live poultry market in Shangrao City. The positive rate of type A and H7 influenza virus in the external environment of live poultry market from the H7N9 cases tracing were significantly higher than those of the free-range farmers, and the differences were statistically significant (χ2=39.16, 31.26, all P<0.05). The positive rate of type A and H7 influenza viruses in the traceability live poultry market was higher than those of daily monitoring, and the differences were statistically significant (χ2=7.68, 10.96, all P<0.05). The positive rate of type A and H7 influenza virus after closing the live poultry market for one week or two weeks decreased more than before. The risk value of influenza A gradually decreased; among the closing time of one week and two weeks the risk values of influenza A were 0.301 (0.192-0.472) and 0.077 (0.048-0.142) respectively, both of which were statistically significant (P<0.05), and the risk values of influenza H7 were 0.251 (0.162-0.390) and 0.021 (0.008-0.055) respectively, both of which were statistically significant (P<0.05). Both the influenza A and H7 positive rates were at a low level within one week after the resumption of the live poultry market, without significant increase. Conclusion Closure of live poultry markets for more than 2 weeks can effectively reduce the risk of avian influenza virus contamination in the external environment and human exposure to avian influenza virus A (H7N9), and the complete closure of the live poultry market plays an important role in the control of the epidemic.