1. School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, P.R China
2. National Health Commission (NHC) Key Laboratory of Enteric Pathogenic Microbiology, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, Jiangsu, P.R China
3. School of Public Health, Southeast University, Nanjing, P.R China
4. Institute of Global Public Health and Emergency Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, P.R China