[1] Univ Witwatersrand, Clin HIV Res Unit, Themba Lethu Clin, Johannesburg, South Africa
[2] Univ Witwatersrand, Dept Med, ZA-2001 Johannesburg, South Africa
[3] Univ Witwatersrand, Dept Obstet & Gynecol, ZA-2001 Johannesburg, South Africa
[4] Univ Witwatersrand, Dept Anat Pathol, ZA-2001 Johannesburg, South Africa
[5] Univ Cape Town, Inst Infect Dis & Mol Med, ZA-7925 Cape Town, South Africa
[6] Groote Schuur Hosp, Natl Hlth Lab Serv, ZA-7925 Cape Town, South Africa
[7] Univ N Carolina, Dept Infect Dis, Ctr AIDS Res & Allied Hlth Sci & Pathol, Chapel Hill, NC USA
[8] Wistar Inst Anat & Biol, Philadelphia, PA 19104 USA