1. National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention; Beijing China
2. Shijingshan Center for Disease Control and Prevention; Beijing China
3. University of North Carolina at Chapel Hill, Project-China; Guangzhou China
4. Guangdong Provincial Center for Skin Diseases and STI Control; Guangzhou China
5. College of Public Health; University of South Florida; Tampa FL USA
6. Department of Epidemiology; Fielding School of Public Health; University of California; Los Angeles CA USA
7. Beijing Human Resources and Social Security Bureau; Beijing China
8. Zhejiang Provincial People's Hospital; Hangzhou China