1. Infectious Disease and International Health, Department of Medicine, Dartmouth Hitchcock Medical Center , Lebanon, New Hampshire , USA
2. Geisel School of Medicine at Dartmouth , Hanover, New Hampshire , USA
3. Infectious Diseases, Universidade Federal de Ciências da Saúde de Porto Alegre , Porto Alegre , Brazil
4. White River Junction VA Medical Center , Hartford, Vermont , USA