1. Epidemiology , Biostatistics and Prevention Institute, Department of Public and Global Health, Division of Infectious Diseases, World Health Organization Collaborating Centre for Travelers’ Health, , Zurich 8001 , Switzerland
2. University of Zurich , Biostatistics and Prevention Institute, Department of Public and Global Health, Division of Infectious Diseases, World Health Organization Collaborating Centre for Travelers’ Health, , Zurich 8001 , Switzerland
3. Division of Epidemiology , Human Genetics & Environmental Sciences, , Houston, TX 77030 , USA
4. University of Texas School of Public Health , Human Genetics & Environmental Sciences, , Houston, TX 77030 , USA
5. Division of Infectious Diseases and Travel Medicine, Mount Auburn Hospital , Cambridge, MA 02138 , USA
6. Faculty of Medicine, Harvard Medical School , Boston, MA 02115 , USA
7. College of Public Health , Medical and Veterinary Sciences, , Townsville, Queensland 4810 , Australia
8. James Cook University , Medical and Veterinary Sciences, , Townsville, Queensland 4810 , Australia
9. School of Public Health , Faculty of Health Sciences, , Johannesburg 2193 , South Africa
10. University of the Witwatersrand , Faculty of Health Sciences, , Johannesburg 2193 , South Africa