1. Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, P.R. China
2. Department of Geriatric Respiratory and Critical Care, Anhui Geriatric Institute, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, P.R. China
3. Department of Pathogen Biology and Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, Anhui 230022, P.R. China