1. Food Safety Monitoring and Evaluation Department, Guangxi Zhuang Autonomous Region Centre for Disease Control and Prevention (Guangxi CDC), Nanning, China
2. Department of Epidemiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
3. Infectious Diseases Department, The Fourth People’s Hospital of Nanning, Nanning, China
4. Infectious Disease Control and Prevention Department, Guiping Center for Disease Control and Prevention (Guiping CDC), Guigang, China
5. Maternity Department, Guiping People’s Hospital, Guigang, China