1. Division of Epidemiology, University of California, Berkeley, CA, USA
2. Centre for Communicable Diseases, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
3. Department of Economics, University of California, Berkeley, CA, USA
4. Goldman School of Public Policy, University of California, Berkeley, CA, USA
5. Division of Biostatistics, University of California, Berkeley, CA, USA
6. Division of Infectious Disease and Geographic Medicine, Stanford University, Stanford, CA, USA