1. NIDDK, LBC, National Institutes of Health, 8 Center Drive, Bethesda, Maryland 20892-0815, United States
2. Division of Infectious Diseases, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, United States
3. International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh (ICDDR,B), Mohakhali, 1212, Dhaka, Bangladesh
4. Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115, United States
5. Department of Immunology and Infectious Diseases, Harvard School of Public Health, 677 Huntington Avenue, Boston, Massachusetts 02115, United States