1. University of Calgary , Department of Medicine, Division of Infectious Diseases, Calgary, Alberta , Canada
2. University of Texas Medical Branch , Department of Medicine, Division of Infectious Diseases, Galveston, Texas , USA
3. Universidad Peruana Cayetano Heredia , Department of Medicine, Division of Infectious Diseases, Lima , Peru
4. University of Alberta , Department of Pathology, Division of Microbiology, Edmonton, Alberta , Canada