1. From the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B): Centre for Health and Population Research, Dhaka, Bangladesh (RR, DSA, PS, SMA, GA, and MY); the MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London, United Kingdom (SEN); and the Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR (GF)