1 Operational Research Unit, Medical Department, Operational Centre Brussels, Medecins sans Frontieres, MSF- Luxembourg, Luxembourg, Germany Medecins sans Frontieres, Geneva, Switzerland Department of Molecular and Cellular Interactions, Flemish Institute of Biotechnology, Brussels, Belgium Department of Microbiology, Institute of Tropical Medicine, Antwerp, Belgium Medecins Sans Frontieres, Addis Ababa, Ethiopia Operational Centre Brussels, Medecins sans Frontieres- Luxembourg (Direction General), Luxembourg, Germany International Union against Tuberculosis and Lung Disease, Centre for Operational Research, Paris, France London School of Hygiene and Tropical Medicine, London, UK.