1. Medical Division, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, Maryland 217021;
2. Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Washington, D.C. 203072;
3. Post 02149, Israel Defense Force Medical Corps, Israel3; and
4. Unité de Pathogénie Microbienne Moléculaire, Unité U389 de l’Institut National de la Santé et de la Recherche Médicale, Institut Pasteur, 75015, Paris, France4