1. School of Public Health, Guangxi Medical University, Nanning, China.
2. Guangxi Key Laboratory of AIDS Prevention and Treatment, Guangxi Medical University, Nanning, China.
3. The First Affiliated Hospital, Chongqing Medical University, Chongqing, China.
4. School of Public Health, Xinjiang Medical University, Xinjiang, China.
5. School of Public Health, Chongqing Medical University, Chongqing, China.
6. National Center for STD Control, Chinese Center for Disease Control and Prevention, Nanjing, China.
7. State Key Laboratory for Infectious Disease Prevention and Control and National Center for AIDS/STD Control and Prevention (NCAIDS), Chinese Center for Disease Control and Prevention, Beijing, China.