Progress Virology

Chinese Science Bulletin

, Volume 58, Issue 26, pp 3183-3187

Open Access This content is freely available online to anyone, anywhere at any time.

Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage

  • QingYe ZhuangAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , SuChun WangAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology CenterCollege of Animal Science and Veterirary Medcine, Qingdao Agricultural University
  • , MeiLi WuAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology CenterCollege of Animal Science and Veterirary Medcine, Qingdao Agricultural University
  • , Shuo LiuAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , WenMing JiangAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , GuangYu HouAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , JinPing LiAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , KaiCheng WangAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
  • , JianMin YuAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center
    • , JiMing ChenAffiliated withChina National Avian Influenza Professional Laboratory, China Animal Health and Epidemiology Center Email author 
    • , JiWang ChenAffiliated withThe Institute for Personalized Respiratory Medicine, University of Illinois at Chicago

Abstract

Dozens of human cases infected with H7N9 subtype avian influenza virus (AIV) have been confirmed in China since March, 2013. Distribution data of sexes, ages, professions and regions of the cases were analyzed in this report. The results showed that the elderly cases, especially the male elderly, were significantly more than expected, which is different from human cases of H5N1 avian influenza and human cases of the pandemic H1N1 influenza. The outbreak was rated as a Grade III (severe) outbreak, and it would evolve into a Grade IV (very severe) outbreak soon, using a method reported previously. The H7N9 AIV will probably circulate in humans, birds and pigs for years. Moreover, with the driving force of natural selection, the virus will probably evolve into highly pathogenic AIV in birds, and into a deadly pandemic influenza virus in humans. Therefore, the H7N9 outbreak has been assumed severe, and it is likely to become very or extremely severe in the future, highlighting the emergent need of forceful scientific measures to eliminate any infected animal flocks. We also described two possible mild scenarios of the future evolution of the outbreak.

Keywords

H7N9 avian influenza virus outbreak epidemiology risk