1. Department of Infectious Disease, Shanghai Ninth People's Hospital, Shanghai 200011, P.R. China
2. Department of Infectious Disease, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
3. Department of Infectious Diseases, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China