1. Beijing Tropical Medicine Research Institute, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
2. Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai 200040, China
3. Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
4. Infectious Disease Research Institute (IDRI), 1616 Eastlake Avenue East, Seattle, WA, USA