1. Ethiopian-Netherlands AIDS Research Project (ENARP), Ethiopian Health and Nutrition Research Institute (EHNRI), Addis Ababa, Ethiopia
2. Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
3. National Referral Laboratory for AIDS, EHNRI, Addis Ababa, Ethiopia
4. Ethiopian Red Cross Society-National Blood Transfusion Service, Addis Ababa, Ethiopia
5. AIDS/STD Control Team, Ministry of Health, Addis Ababa, Ethiopia
6. Division of Public Health and Environment, Municipal Health Service, Amsterdam, The Netherlands