Sexual and mother-to-child transmission of the human immunodeficiency virus type 1: a review.
OBJECTIVE
Sexual and mother-to-child transmission of the human immunodeficiency virus (HIV) type 1 occurs only with a low percentage of infection. 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).


METHODS
We analyzed the presence of HIV in various ejaculates of the same HIV-infected patients, as well as in the cervico-vaginal fluid. We have studied the mechanism of transmission from mother to child, by analyzing the cell-to-cell 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 in mobile spermatozoa. The trophoblast can be infected by HIV with a strain dependence and also transiently. By analyzing the tissue of the fetus, it was found that only some organs are infected, confirming the cell-to-cell transmission between the mother and child and not a true vertical transmission through the germinal lines.


CONCLUSIONS
HIV is not always present in the genital secretion, explaining the low rate of sexual transmission. Mother-to-child transmission occurs during pregnancy but often after the second trimester and at delivery after cell-to-cell or blood transmission, respectively.
INSERM Unité de Recherche sur les Rétrovirus et Maladies, Technologique de Luminy, Marseille, France.
J C
JC
Chermann
D005260:Female; D015658:HIV Infections / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D011247:Pregnancy; D012747:Sexual Partners