[1] Stanford Univ, Dept Med, Div Infect Dis, Stanford, CA 94305 USA
[2] Univ Calif San Francisco, Dept Family & Community Med, San Francisco, CA 94011 USA
[3] Careen Ctr Hlth, Gaborone, Botswana
[4] Tufts Univ, Sch Med, Boston, MA 02111 USA
[5] Cambridge Inst Therapeut Immunol & Infect Dis CITI, Cambridge CB2 0AW, England
[6] Tufts Med Ctr, Div Geog Med & Infect Dis, Boston, MA 02111 USA