1. South African Field Epidemiology Training Programme, National Institute for Communicable Diseases, National Health Laboratory Service, South Africa
2. Centre for HIV and STI, National Institute for Communicable Diseases, National Health Laboratory Service, South Africa
3. Faculty of Health Sciences, School of Health Systems and Public Health, University of Pretoria, South Africa
4. US Centers for Disease Control and Prevention, Global Disease Detection Program, Pretoria, South Africa
5. Division of Global Health Protection, Center for Global Health, US Centers for Disease Control and Prevention, Atlanta, USA
6. Perinatal HIV Research Unit, Faculty of Health Sciences, University of the Witwatersrand, South Africa