1. Department of Chronic Communicable Disease, Center for Disease Control and Prevention of Jiangsu Province, Nanjing, China
2. University of Georgia, College of Public Health, Department of Epidemiology and Biostatistics, Athens, Georgia, USA
3. Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA
4. Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
5. Stanford University, School of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford, California, USA