[1] Univ Saarland, Inst Med Microbiol & Hyg, Homburg, Germany
[2] Inst Natl Rech Sante Publ, Bamako, Mali
[3] Swiss Trop & Publ Hlth Inst, Dept Epidemiol & Publ Hlth, Basel, Switzerland
[4] Univ Basel, Basel, Switzerland
[5] Inst Trop Med, B-2000 Antwerp, Belgium
[6] Univ Hosp Geneva, Div Humanitarian & Trop Med, Geneva, Switzerland