1. Section of Clinical Tropical Medicine, Department of Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, Heidelberg, 69120, Germany.
2. Department of Internal Medicine, Federal University of Pernambuco, Recife, Brazil.
3. Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, England.
4. Fundacao Oswaldo Cruz, Rio de Janeiro, Brazil.
5. Virology and Experimental Therapeutics Laboratory, Aggeu Magalhães Research Center, Recife, Brazil.