Abstract： In the past ten years,we had experienced a series of emerging severe acute respiratory infections (SARI).Some of them became serious public health emergent events,such as severe acute respiratory syndrome (SARS) and novel A/H7N9 avian influenza.Tracing back to 2003,SARS originated from Guangdong province and spread to 29 countries and regions until it was completely controlled.Out of 8 096 probable SARS cases world-wide,774 patients died;the mortality was 9.6％.1 There were 5 327 patients with SARS in China,and 1 002 (19％) of them were health care workers (HCW).Nearly all the HCW got hospital acquired infection since there was no efficient preventive and protective system.However,ten years later,novel A/ H7N9 avian influenza,another emerging infectious disease,was identified in Shanghai City.In the more than two years,there have been a total of 435 cases with the novel A/H7N9 infection,and 166 patients died.The mortality is 38.2％.