Sexually transmitted infections and factors associated with risky sexual practices among female sex workers : A cross sectional study in a large Andean city - Llangarí-Arizo, Luz Marina (Universitat Autònoma de Barcelona. Departament de Medicina) ; Sadiq, S. Tariq (St George's University of London) ; Márquez, Cynthia (Universidad Internacional de Ecuador) ; Cooper, Philip (St George's University of London) ; Furegato, Martina (St George's University of London) ; Zhou, Liqing (St George's University of London) ; Aranha, Luisa (Ministerio de Salud Pública de Ecuador) ; Mateo, Miguel Martín (Grups de Recerca d'Amèrica i Àfrica Llatines- GRAAL (Barcelona, Catalunya)) ; Romero-Sandoval, Natalia (Universitat Autònoma de Barcelona. Departament de Medicina)