title: Risk Distribution of Human Infections with Avian Influenza H7N9 and H5N1 virus in China.
abstract: It has been documented that the epidemiological characteristics of human infections with H7N9 differ significantly between H5N1. However, potential factors that may explain the different spatial distributions remain unexplored. We use boosted regression tree (BRT) models to explore the association of agro-ecological, environmental and meteorological variables with the occurrence of human cases of H7N9 and H5N1, and map the probabilities of occurrence of human cases. Live poultry markets, density of human, coverage of built-up land, relative humidity and precipitation were significant predictors for both. In addition, density of poultry, coverage of shrub and temperature played important roles for human H7N9 infection, whereas human H5N1 infection was associated with coverage of forest and water body. Based on the risks and distribution of ecological characteristics which may facilitate the circulation of the two viruses, we found Yangtze River Delta and Pearl River Delta, along with a few spots on the southeast coastline, to be the high risk areas for H7N9 and H5N1. Additional, H5N1 risk spots were identified in eastern Sichuan and southern Yunnan Provinces. Surveillance of the two viruses needs to be enhanced in these high risk areas to reduce the risk of future epidemics of avian influenza in China.
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Xin-Lou
authors.initials: XL
authors.lastname: Li
authors.affiliation: Department of Biostatistics, College of Public Health and Health Professions &Emerging Pathogens Institute, University of Florida, 100188, Florida, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Sun
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Wan-Jun
authors.initials: WJ
authors.lastname: Chen
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Ruo-Xi
authors.initials: RX
authors.lastname: Sun
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Mai-Juan
authors.initials: MJ
authors.lastname: Ma
authors.affiliation: Department of Environmental and Global Health, College of Public Health and Health Professions, and Emerging Pathogens Institute, University of Florida, 100188, Florid, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Liang
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Hong-Wu
authors.initials: HW
authors.lastname: Yao
authors.affiliation: Division of Infectious Diseases, Global Health Institute, &Nicholas School of the Environment, Duke University, 27710, Durham, NC, USA.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Gray
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Li-Qun
authors.initials: LQ
authors.lastname: Fang
authors.affiliation: The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, P. R. China.
authors.forename: Wu-Chun
authors.initials: WC
authors.lastname: Cao
mesh_terms: D000818:Animals; D001717:Birds / Q000821:virology; D002681:China / Q000453:epidemiology; D005843:Geography; D006801:Humans; D015994:Incidence; D053124:Influenza A Virus, H5N1 Subtype / Q000502:physiology*; D064766:Influenza A Virus, H7N9 Subtype / Q000502:physiology*; D005585:Influenza in Birds / Q000821:virology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008954:Models, Biological; D011336:Probability; D012044:Regression Analysis; D012307:Risk Factors