1. Projet RETRO-CI, 01 BP 1712, Abidjan, Ivory Coast.
2. Division of HIV/AIDS, Center for Infectious Diseases, Centers for Disease Control, Atlanta, GA 30333.
3. Institute for Resource Development Incorporated, 8850 Stanford Boulevard, Suite 4000, Columbia, MD 21045.
4. Centre Ivoirien de Recherche Economique et Sociale, 08 BP 1295, Abidjan, Ivory Coast.
5. Department of Pathology, Faculty of Medicine, University of Abidjan, BP V 166 Abidjan, Ivory Coast.
6. Department of Infectious Diseases, Faculty of Medicine, University of Abidjan, BP V 166 Abidjan, Ivory Coast.