[1] Nagasaki Univ, Inst Trop Med, Dept Int Hlth, Nagasaki 8528523, Japan
[2] Univ Tsukuba, Dept Epidemiol, Grad Sch Comprehens Human Sci, Tsukuba, Ibaraki 3058575, Japan
[3] Kyoto Univ, Disaster Prevent Res Inst, Kyoto 6110011, Japan
[4] Int Ctr Diarrhoeal Dis Res, Dhaka 1000, Bangladesh