[1] Univ Sherbrooke, Ctr Rech Clin, Ctr Hosp, Sherbrooke, PQ, Canada
[2] Polyclin Bordeaux Nord Aquitaine, Bordeaux, France
[3] Univ Liverpool, Liverpool Sch Trop Med, Liverpool L3 5QA, Merseyside, England
[4] Univ Washington, Seattle, WA 98195 USA
[5] Univ N Carolina, Chapel Hill, NC USA
[6] Univ Toronto, Toronto, ON, Canada