1 Specialty Internal Medicine and Quality Department, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia.
2 Division of Infectious Disease, Department of Medicine, Indiana University School of Medicine, Indiana, USA.
3 Division of Infectious Disease, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
4 Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands.
5 University of Zürich, Institute for Epidemiology, Biostatistics and Prevention, WHO Collaborating Centre for Travellers' Health, Department of Global and Public Health, MilMedBiol Competence Centre, Zürich, Switzerland.