1. Medical School of Chinese People’s Liberation Army (PLA), Beijing 100853, China
2. Department of Infectious Diseases, The Fifth Medical Centre of Chinese PLA General Hospital, National Clinical Research Centre for Infectious Diseases, Beijing 100853, China
3. Department of Gastroenterology, First Medical Center of Chinese PLA General Hospital, Beijing 100036, China
4. State Key Laboratory of Pathogenand Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing 100850, China