1. Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana;
2. Department of Economics, Laval University, Quebec City, Canada;
3. Institut de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso;
4. Department of Preventive and Social Medicine, Faculty of Medicine, Laval University, Quebec City, Canada;
5. Société d’Études et de Recherches en Santé Publique, Ouagadougou, Burkina Faso