1. a Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh
2. b Environmental Interventions Unit, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Bangladesh
3. c School of Public Health & Preventive Medicine, Monash University, Melbourne, Australia
4. d School of Civil Engineering, University of Leeds, Leeds, UK
5. h Department of Epidemiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
6. e Department of Public Health Sciences, Clemson University, Clemson, SC, USA
7. g John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
8. f Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, USA