1. University of California, Berkeley School of Public Health, Berkeley, California;
2. Colegio de Ciencias Biologicas y Ambientales, Microbiology Institute, Universidad San Francisco de Quito, Quito, Ecuador;
3. Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia;
4. Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia;
5. Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan