H7N9 influenza virus surveillance in Gansu, China in 2017.

Avian H7N9 influenza virus, which emerged in 2013 China, had caused the fifth wave of peaks in 2016-2017. Gansu Province locate in western China far away from the epicenter of the virus, also detected cases in this wave. During the monitoring, five human cases with H7N9 virus infection, three cases in Jiuquan and two cases in Zhangye, were reported and investigated.

The re-emergence of highly pathogenic avian influenza H7N9 viruses in humans in mainland China, 2019.

After no reported human cases of highly pathogenic avian influenza (HPAI) H7N9 for over a year, a case with severe disease occurred in late March 2019. Among HPAI H7N9 viral sequences, those recovered from the case and from environmental samples of a poultry slaughtering stall near their home formed a distinct clade from 2017 viral sequences. Several mutations possibly associated to antigenic drift occurred in the haemagglutinin gene, potentially warranting update of H7N9 vaccine strains.

Comparing the similarity and difference of three influenza surveillance systems in China.

Three main surveillance systems (laboratory-confirmed, influenza-like illness (ILI) and nationwide Notifiable Infectious Diseases Reporting Information System (NIDRIS)) have been used for influenza surveillance in China. However, it is unclear which surveillance system is more reliable in developing influenza early warning system based on surveillance data. This study aims to evaluate the similarity and difference of the three surveillance systems and provide practical knowledge for improving the effectiveness of influenza surveillance.