1. CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
2. CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
3. Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
4. Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, No 111, Ren Ai Road, Dushu Lake Higher Education Town, Suzhou Industrial Park (SIP), Suzhou 215123, P. R. China
5. Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, P. R. China
6. Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
7. Office of Director-General, Chinese Center for Disease Control and Prevention, Beijing 102206, P. R. China