1. Health Systems and Infectious Diseases Division, International Centre for Diarrheal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212, Bangladesh
2. Department of Pediatrics, University of British Columbia, Vancouver V6H 3V4, Canada
3. Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205