1. HIV/AIDS and Retrovirology Branch, Division of AIDS, STD and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333.
2. Hopital Militaire de Yaoundé, Yaoundé, Cameroon
3. Projet RETRO-CI, Abidjan, Ivory Coast and International Activity Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS/TB/STD, CDC, Atlanta, Georgia 30333
4. Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294