1. School of Medicine; University of California, San Francisco; San Francisco California USA
2. Environmental Health and Ecological Sciences Department; Ifakara Health Institute; Bagamoyo Tanzania
3. Environmental Health and Ecological Sciences Department; Ifakara Health Institute; Ifakara Tanzania
4. Eck Institute for Global Health, University of Notre Dame; Indianapolis Indiana USA
5. MRC International Statistics and Epidemiology Group; London School of Hygiene & Tropical Medicine; London UK
6. Public Health and Epidemiology; Swiss Tropical and Public Health Institute; Basel Switzerland