Gao R1, Cao B, Hu Y, Feng Z, Wang D, Hu W, et al. N Engl J Med. 2013 May 16;368(20):1888-97.
Background: Infection of poultry with influenza A subtype H7 viruses occurs worldwide, but the introduction of this subtype to humans in Asia has not been observed previously. In March 2013, three urban residents of Shanghai or Anhui, China, presented with rapidly progressing lower respiratory tract infections and were found to be infected with a novel reassortant avian-origin influenza A (H7N9) virus.