1. Weill Cornell Medical College and the New York Center for Travel and Tropical Medicine, New York, NY, USA
2. Fleet Street Travel Clinic, London EC4Y 1AA, UK
3. University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
4. Department of Global Health, Boston University School of Public Health, Boston, MA, USA
5. Section of Infectious Diseases, Department of Medicine, Boston Medical Center, Boston, MA, USA