1 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. Electronic address: nathan.lo@stanford.edu.
2 Department of Medicine, University of Toronto, Toronto, ON, Canada; Division of Infectious Diseases, Toronto General Hospital, University Health Network, Toronto, ON, Canada; Division of General Internal Medicine, Toronto General Hospital, University Health Network, Toronto, ON, Canada.
3 Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
4 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.