Emerging Infectious Diseases (Jan 2018)

Changing Geographic Patterns and Risk Factors for Avian Influenza A(H7N9) Infections in Humans, China

  • Jean Artois,
  • Hui Jiang,
  • Xiling Wang,
  • Ying Qin,
  • Morgan Pearcy,
  • Shengjie Lai,
  • Yujing Shi,
  • Juanjuan Zhang,
  • Zhibin Peng,
  • Jiandong Zheng,
  • Yangni He,
  • Madhur S. Dhingra,
  • Sophie von Dobschuetz,
  • Fusheng Guo,
  • Vincent Martin,
  • Wantanee Kalpravidh,
  • Filip Claes,
  • Timothy Robinson,
  • Simon I. Hay,
  • Xiangming Xiao,
  • Luzhao Feng,
  • Sheng Wei,
  • Hongjie Yu

DOI
https://doi.org/10.3201/eid2401.171393
Journal volume & issue
Vol. 24, no. 1
pp. 87 – 94

Abstract

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The fifth epidemic wave of avian influenza A(H7N9) virus in China during 2016–2017 demonstrated a geographic range expansion and caused more human cases than any previous wave. The factors that may explain the recent range expansion and surge in incidence remain unknown. We investigated the effect of anthropogenic, poultry, and wetland variables on all epidemic waves. Poultry predictor variables became much more important in the last 2 epidemic waves than they were previously, supporting the assumption of much wider H7N9 transmission in the chicken reservoir. We show that the future range expansion of H7N9 to northern China may increase the risk of H7N9 epidemic peaks coinciding in time and space with those of seasonal influenza, leading to a higher risk of reassortments than before, although the risk is still low so far.

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