1. School of Medicine, Jiangsu University, Zhenjiang, China
2. Eastern Theater Command Centers for Disease Prevention and Control, Nanjing, China
3. Centre for Diseases Prevention and Control of Yandu District, Yancheng, China
4. Centre for Diseases Prevention and Control of Yancheng, Yancheng, China
5. Chinese People’s Liberation Army Center for Disease Control and Prevention, Beijing, China