1. Liverpool School of Tropical Medicine, Liverpool, United Kingdom;
2. The University of Georgia, College of Public Health, Department of Environmental Health Science, Athens, Georgia;
3. Indira Medical College, Nagpur, India;
4. Department of Medicine, University of California San Francisco, San Francisco, California and School of Public Health, University of California, Berkeley, California;
5. Georgetown University School of Medicine, Washington, DC; and
6. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland