1. Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, CA, USA
2. Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
3. Travel Medicine Center, Mount Auburn Hospital, Cambridge, MA, USA
4. Department of Medicine, Harvard Medical School, Boston, MA, USA
5. Division of Infectious Diseases and Travel Medicine, Mount Auburn Hospital, Cambridge, MA, USA