1. Department of Internal Medicine, Division of Infectious Diseases, Washington University, St. Louis, Missouri, USA
2. Vaccine R&D Center, University of California, Irvine, Irvine, California, USA
3. Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, USA
4. Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
5. Division of Biostatistics, Washington University, St. Louis, Missouri, USA
6. Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
7. Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
8. Medicine Service, Veterans Affairs Medical Center, St. Louis, Missouri, USA