1. Save the Children, Dhaka 1212, Bangladesh
2. Health Research Institute, Faculty of Health, University of Canberra, Canberra, ACT 2617, Australia
3. Maternal and Child Health Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka 1212, Bangladesh
4. Department of Social Anthropology, School of Social & Political Science, University of Edinburgh, 15a George Square, Edinburgh EH8 9LD, Scotland, UK