SEXUAL AND MOTHER-TO-CHILD TRANSMISSION OF THE HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 - A REVIEW

PROBLEM: Sexual and mother-to-child transmission of the human immunode ficiency virus (HIV) type 1 occurs only with a low percentage of infec tion. Many instances of sexual intercourse result in no transmission, and only 20% of children are infected from seropositive mothers (3% in mothers treated with azidothymidine). METHOD OF STUDY: We analyzed th e presence of HIV in various ejaculates of the same HIV-infected patie nts, as well as in the cervico-vaginal fluid. We have studied the mech anism of transmission from mother to child, by analyzing the cell-to-c ell transmission in the trophoblast RESULTS: Some ejaculates collected at different times from the same HIV-infected males are free of virus , explaining the low rate of sexual transmission. We never found HIV i n mobile spermatozoa. The trophoblast can be infected by HIV with a st rain dependence and also transiently By analyzing the tissue of the fe tus, it was found that only some organs are infected, confirming the c ell-to-cell transmission between the mother and child and not a true v ertical transmission through the germinal lines. CONCLUSIONS: HIV is n ot always present in the genital secretion, explaining the low rate of sexual transmission. Mother-to-child transmission occurs during pregn ancy but often af ter the second trimester and at delivery after cell- to-cell or blood transmission, respectively.