1. Molecular Microbiology and Immunology,1
2. International Health,2 and
3. Departments of Medicine3 and
4. Departments of Environmental Health Sciences,4
5. Epidemiology,5 School of Hygiene and Public Health, and
6. Pathology,6 School of Medicine, The Johns Hopkins University, Baltimore, Maryland;
7. Departments of Pathology and Animal Research, The George Washington University Medical Center, Washington, D.C.7; and
8. Department of Aerobiology and Product Evaluation, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland8