1. From the Tropical Gastroenterology and Nutrition Group, University of Zambia School of Medicine, Lusaka, Zambia (PK, MK, RB, VY, MF, IZ, and FY); the Institute of Cell and Molecular Science, Barts & The London School of Medicine and Dentistry, London, United Kingdom (PK, IZ, and IRS); the London School of Hygiene and Tropical Medicine, London, United Kingdom (PK and JT); the Tropical Diseases Res