1. Infectious Diseases Research Group, Siebens–Drake Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
2. Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, PO Box 174 Correo 22, Santiago, Chile
3. Infectious Diseases Research Group, Siebens–Drake Research Institute, Department of Medicine, University of Western Ontario, London, ON N6A 5C1, Canada