[1] Tulane Univ, Dept Social Behav & Populat Sci, Sch Publ Hlth & Trop Med, New Orleans, LA 70112 USA
[2] Tulane Univ, Dept Epidemiol, Sch Publ Hlth & Trop Med, 1440 Canal St, New Orleans, LA 70112 USA
[3] Tulane Univ, Murphy Inst, Sch Liberal Arts, New Orleans, LA 70118 USA
[4] London Sch Hyg & Trop Med, Infect Dis Program, London WC1E 7HT, England
[5] Univ Cartagena, Dept Med, Cartagena 130014, Colombia