Maternal and cord samples from HIV-seropositive women and their infants in Zimbabwe, where subtype C is the predominant strain of HIV, were analyzed to determine the frequency of detection of HIV RNA and DNA. HIV RNA was detected in 90% of maternal and in 38% of cord plasma at levels at least 25% of maternal plasma. Heteroduplex mobility assays and sequencing of virus envelope (C2-V5) demonstrated closely related, but unique, subtype C viruses in maternal and cord RNA, and a significantly greater frequency of cord viremia among women with homogenous, compared with heterogeneous viral envelope RNA. Quantification of RNA, measures of envelope viral diversity, and phylogenetic analysis of maternal and cord plasma RNA provide evidence for the frequent exposure and potential transmission of HIV from mother to infant before birth.
Address correspondence and reprint requests to David A. Katzenstein, Center for AIDS Research, Division of Infectious Diseases and Geographic Medicine, S156, Stanford University Medical Center, Stanford, California 94305-5107 U.S.A.; e-mail: email@example.com
This study was presented in part at the Conference on Global Strategies for the Prevention of HIV Transmission from Mothers to Infants, Montréal, Québec, Canada, 1999 (Abstract 451) and the XIII International AIDS Conference, Durban, South Africa, July 2000 (Abstract MoPeB2223).
All samples were collected after obtaining verbal informed consent to use blood samples under protocol approved by the Medical Research Council of Zimbabwe. Blood samples were unlinked from identifiers, assigned code numbers and laboratory testing and analysis were performed under an exempt protocol approved by the Stanford Panel of Human Subjects.
Manuscript received August 15, 2000; accepted October 17, 2000.
© 2000 Lippincott Williams & Wilkins, Inc.