1. Department of Microbiology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
2. Suzhou Research Institute of Shandong University, Suzhou, Jiangsu, China
3. Shandong Center for Disease Control and Prevention, Jinan, Shandong, China
4. Qingdao Center for Disease Control and Prevention, Qingdao, Shandong, China
5. Binzhou Center for Disease Control and Prevention, Binzhou, Shandong, China
6. Weihai Center for Disease Control and Prevention, Weihai, Shandong, China
7. Zibo Center for Disease Control and Prevention, Zibo, Shandong, China
8. Yantai Center for Disease Control and Prevention, Yantai, Shandong, China