1. National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and Prevention Beijing China
2. Dehong Dai and Jingpo Autonomous Prefecture Center for Disease Control and Prevention China
3. Dehong Dai and Jingpo Autonomous Prefecture People's Hospital China
4. School of Chemistry and Molecular Biosciences University of Queensland St Lucia Australia
5. Department of Epidemiology UCLA Fielding School of Public Health Los Angeles California USA