Vertical transmission of HIV [letter]

Prospective studies from Zambia and Zaire have found a vertical transmission rate of human immunodeficiency virus (HIV) of 39%. In contrast the European Collaborative Study documented a rate of only 13%. The higher rate in Africa has been attributed to the greater proportion of women with HIV disease a higher loss of babies to follow up and breastfeeding. The author suggests that greater attention should be given to the possible role of chorioamnionitis in raising the risk of HIV transmission to the fetus. This condition is more prevalent in Africa than in developed countries. Infection with Candida Ureaplasma urealyticum Mycoplasma hominis and other bacteria can occur through intact membranes and result in asymptomatic chronic intrauterine infection with intense inflammation of the placenta. In the Zairian study 39% of infants whose placentas showed evidence of severe chorioamnionitis contracted perinatal HIV infection compared with 18% without severely infected placentas. There is some evidence that immunodeficiency may predispose women to chorioamnionitis. In the Zairian study severe chorioamniotitis was found in 21% of women with acquired immunodeficiency syndrome (AIDS) 1% of HIV-positive women without AIDS and 3% of seronegative controls. Prematurity which increases the risk of maternal-fetal HIV transmission is often caused by chorioamnionitis. Microbiological and histological examinations of placentas are urged to clarify the role o chorioamnionitis in vertical HIV transmission.