1. Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
2. Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Ft Detrick, Maryland
3. John F. Kennedy Medical Center, Monrovia, Liberia
4. Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland