1 Instituto de Microbiologia, Faculdade de Medicina de Lisboa, P-1649-028 Lisbon, Portugal. Electronic address: t.hanscheid@medicina.ulisboa.pt.
2 Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Lisbon, Portugal.
3 Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.