1 Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam Institute for Infection and Immunity, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, Netherlands.
2 Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, Netherlands.
3 Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam Institute for Infection and Immunity, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, Netherlands. Electronic address: a.goorhuis@amsterdamumc.nl.