1. Division of Epidemiology, The Ohio State University, Columbus, Ohio
2. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
3. Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
4. Lighthouse Trust, Lilongwe, Malawi
5. UNC Project, Lilongwe, Malawi
6. Department of Health Behavior, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
7. Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland