[1] London Sch Hyg & Trop Med, Dept Infect & Trop Dis, London WC1E 7HT, England
[2] Med Sans Frontieres United Kingdom, London EC1N 8QX, England
[3] Med Sans Frontieres Swiss Sect, CH-1211 Geneva 21, Switzerland
[4] Univ Hosp Geneva, CH-1211 Geneva 14, Switzerland
[5] Univ Geneva, Travel & Migrat Med Unit, CH-1211 Geneva 14, Switzerland
[6] Epictr, F-75011 Paris, France
[7] Med Sans Frontieres Belgian Sect, B-1090 Brussels, Belgium