Investigation of geographic relationship between farmer's market with live birds and human infections with avian influenza A (H7N9) virus based on internet data analysis / 中华流行病学杂志

ABSTRACT

Objective Farmer' s markets with live birds (FMLB) are key sites where human infections by influenza A virus subtype H7N9 happened.Approximately 80％ cases have exposed to FMLB.This study is to investigate the geographic relationship between FMLB and human cases based on analysis of internet data of their geographic locations.Methods Using big data from internet,we searched all FMLB in the cities where the human cases have been reported,then analyzed geographic relations,and evaluated the possibility of visits of the patients to the FMLB around them.The densities of FMLB,population and live poultries were also analyzed.Results Forty-two cities and 10 615 markets were included in the study.It is indicated that the number of human cases has positive correlations with the population density,the number and density of markets.Except three markets in Foshan,human cases have been reported within 5 km of 10 of 13 markets,which shows that the live bird trading is highly relevant with the distribution of cases.We identified 13 hot spots in the cities including Hangzhou,Shenzhen,et al,where clustered cases have emerged.Conclusion The numbers of human cases are significantly high in cities where FMLB are detected positive for H7N9 virus.These virus positive markets usually affect the people's residence within 5km area.The number and location of FMLB in cities should be re-evaluated and re-planed for healthy city where the risk of residents infecting avian influenza virus is greatly reduced or eliminated.