1. Department of Pathogenic Biology, Qingdao University Medical College, Qingdao, China
2. Department of Clinical Laboratory, Zibo Central Hospital, Zibo, China
3. Pathology Department, The Affiliated Hospital of Qingdao University, Qingdao, China
4. Municipal Centre of Disease Control and Prevention of Qingdao, Qingdao Institute of Prevention Medicine, Qingdao, Shandong Province, China