1. Department of Medicine and Microbiology, University of Washington School of Medicine; University of Washington, Seattle, Washington 98104.
2. Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington 98104.
3. Department of Infectious Diseases, University of Dakar, Dakar, Senegal.
4. Institute of Public Health, Dakar, Senegal.
5. Department of Medicine, University of Washington School of Medicine; University of Washington, Seattle, Washington 98104.
6. Department of Pathology, University of Washington School of Medicine, University of Washington, Seattle, Washington 98104.