Apparent vertical transmission of human immunodeficiency virus type 1 by breast-feeding in Zambia

Mother-to-infant HIV transmission: timing, risk factors and prevention

Identifying when--during pregnancy, delivery or the postnatal period--transmission of human immunodeficiency virus (HIV) from mother to infant usually takes place is critical to the development of methods to prevent maternal-infant transmission. Evidence is reviewed in this paper as to whether transmission occurs prepartum (early or late in gestation), intrapartum, or postpartum with breast feeding. Evidence in support of the notion of prepartum transmission has come from isolation of HIV from aborted fetal organs, comparison of maternal-child viral genotypes and study of neonatal cell-mediated immune responses. Evidence against prepartum transmission is that fewer than half of the children later known to be HIV-infected can be identified by virological tests carried out close to birth. A reduced rate of transmission in infants delivered by Caesarean section, and a reduced risk of transmission to second-born twins delivered vaginally, offers support to the view that intrapartum factors influence the risk of HIV transmission. Transmission through breast feeding can occur if a mother is infected postpartum and seems to pose some additional risk if she is already infected at parturition. The risk of infection increases with the stage of maternal HIV disease, but specific immunological, clinical and viral characteristics need to be investigated further. A clinical trial of zidovudine, used during late pregnancy and delivery and given to the infant at birth, has reported a significant reduction in transmission. Primary prevention of HIV infection in women remains a principal priority.

Maternal health in the age of AIDS: implications for health services in developing countries

In developing countries, the HIV/AIDS epidemic will have a major impact on all phases of women's reproductive lives, and will alter many standard approaches to the management of MCH (maternal and child health) services related to fertility regulation, pregnancy, delivery and the postpartum period. AIDS-related increased caseloads, occupational risk to health workers and reduced resources will further compromise MCH services. MCH programme managers and service providers need to better understand the nature of both technical and service-related issues intersecting both the MCH and AIDS fields to mitigate this impact.

Dry and tight: sexual practices and potential AIDS risk in Zaire

Both men and women in central Zaire like a 'dry, tight' vagina because it increases pleasure during sexual intercourse. In focus group interviews, they described wiping and washing procedures, as well as 30 different substances, mostly leaves and powders, that women can insert into the vagina to produce the desired effects. Women who use leaves said they crush them, insert them for several hours, then remove them before intercourse. Women who insert powders leave them in place during intercourse. Individual interviews with 99 women (half of them unmarried prostitutes and half married women) showed that over one-third of each group had used intravaginal drying or tightening substances at some time. Vaginal examinations by a physician revealed that several of the substances cause inflammatory lesions of the vagina and cervix. Furthermore, some products cause extreme dryness that could foster epithelial trauma during coitus, both for the woman and for her partner. Breaks in the epithelium may promote the passage of organisms that cause AIDS and other sexually-transmitted diseases. Thus the sexual practices of drying and tightening the vagina may be increasing the risk of infection.

Inactivation of human immunodeficiency virus type I in human milk: effects of intrinsic factors in human milk and of pasteurization

Human milk was inoculated with human immunodeficiency virus type I (HIV-1) or with HIV-1-infected cells in volumes and containers typically used in human milk banks. The inoculated milk was pasteurized at 62.5 degrees C for 30 minutes in a water bath, i.e., conditions currently in use or proposed for human milk pasteurization. The process of HIV-1 inoculation and pasteurization effectively inactivated the infectivity of both cell-free HIV-1 and HIV-1-infected cells. No virus was recovered after the process, even after repeated subculturing in attempts to rescue the virus. Pasteurization reduced the infectious titer of cell-free HIV-1 and HIV-1-infected cells by more than 5 logs and 6 logs respectively. Human milk contains one or more components that inactive HIV-1 but that are not toxic for the cells used to replicate virus. These components have not been identified, but physical and solubility properties are consistent with characteristics of lipids.

Risk of human immunodeficiency virus type 1 transmission through breastfeeding

Detection of human immunodeficiency virus type 1 (HIV-1) in breast milk by culture and polymerase chain reaction does not necessarily mean that breastfeeding is a route of transmission, although evidence from several case-reports points in that direction. We undertook a systematic review of published studies meeting criteria that allowed determination of quantitative risk of transmission via breastfeeding. Based on four studies in which mothers acquired HIV-1 postnatally, the estimated risk of transmission is 29% (95% Cl 16-42%). Analysis of five studies showed that when the mother was infected prenatally, the additional risk of transmission through breastfeeding, over and above transmission in utero or during delivery, is 14% (95% Cl 7-22%). Where there are safe alternatives to breastfeeding, universal named testing of pregnant women would provide an opportunity to advise more infected women not to breastfeed and might thereby reduce the number of vertically infected children. Since breastfeeding protects against infant deaths from infectious diseases, breastfeeding is still recommended where infectious diseases are a common cause of death in childhood, despite the additional risk of HIV transmission.

Clinical manifestations, management and therapy of HIV infection in children

Perinatal infection accounts for the majority of cases of HIV infection in children both in developed and developing countries. Transmission may occur in utero, intrapartum or postpartum as a result of breast-feeding. The actual risk of transmission through breast-feeding is unknown. The majority of infants reported to be infected through breast milk have been infected as a result of a recently acquired HIV infection in the mother. Infants with HIV infection frequently present with clinical symptoms early in life. There is a broad spectrum of clinical findings in paediatric HIV infection, with opportunistic infections and multiorgan system involvement being common. The management of infants born to seropositive mothers includes routine paediatric care as well as careful clinical and laboratory monitoring for evidence of HIV infection. Infants who are seronegative with normal clinical and immunological findings at 18 months of age are considered uninfected. The prognosis and outcome of infants with HIV infection have improved considerably with earlier diagnosis and the availability of specific antiviral therapy. Modalities of therapy include frequent medical evaluation, aggressive diagnosis and treatment of infection, prophylaxis for Pneumocystis carinii infection, the use of intravenous gamma-globulin and specific antiviral therapy, such as zidovudine, didanosine or other drugs in development through clinical trials. HIV infection in children is a chronic illness and requires a comprehensive, family-oriented approach to care. With longer survival, children require support systems and an atmosphere of care and understanding to give them a good quality of life as well as prolonged survival.

The situation in Africa

More than three million women world-wide are infected with HIV, and women will constitute 40% of the new AIDS cases in 1990-1991. Unlike in the industrialized world, HIV in Africa is heterosexually transmitted and thus affects at least as many women as men. Already the leading cause of death in a major African city, HIV may be spreading to rural areas. In spite of improvement in surveillance, under-reporting makes it difficult to project trends, document differences within and between urban and rural areas, and identify at-risk groups. Increasing evidence shows that STDs play a major role in spreading the HIV epidemic. Male-to-female transmission is more efficient owing to factors related to the pathogen and the host. Ulcerative STDs such as chancroid, syphilis and herpes facilitate HIV entry through mucosal discontinuation and recruitment of HIV target cells. The role of non-ulcerative STDs such as gonorrhoeal, chlamydial and trichomonal infections needs further elucidation. Lack of circumcision, traditional healing practices and oral contraceptives may affect the risk of viral transmission, but may not be major or modifiable risk factors. Pregnancy and pregnancy-associated immune alterations do not seem to affect the clinical course of HIV/AIDS in African women or impair immunocompetence. Maternal HIV can adversely affect pregnancy outcome in Africa, causing low birth-weight, prematurity, intrauterine and intrapartum fetal death. The risk for these outcomes is likely to depend on the degree of immunological and clinical deterioration. Breast-feeding does not appreciably increase the risk of HIV transmission to the infant and should be actively promoted in Africa. Control of HIV/AIDS in Africa, in the absence of an effective vaccine, will focus on behavioural changes through health education and condom use. High frequency STD transmitter core groups, mainly prostitutes and their clients, are currently the target of prevention campaigns which are proving to be successful and affordable.

Postnatal transmission of human immunodeficiency virus type 1 from mother to infant. A prospective cohort study in Kigali, Rwanda

BACKGROUND

Although transmission of human immunodeficiency virus type 1 (HIV-1) from mother to infant has been well documented during pregnancy and delivery, little is known about the possible transmission of HIV-1 during the postnatal period.

METHODS

We conducted a prospective cohort study in Kigali, Rwanda, of 212 mother-infant pairs who were seronegative for HIV-1 at delivery. All the infants were breast-fed. The subjects were followed at three-month intervals, with Western blot assays for antibodies to HIV-1 and testing of mononuclear cells by a double polymerase chain reaction (PCR) using three sets of primers. To evaluate potential risk factors, each mother who seroconverted was matched with three seronegative control women.

RESULTS

After a mean follow-up of 16.6 months, 16 of the 212 mothers became seropositive for HIV-1. Of their 16 infants, 9 became seropositive. One infant was excluded from the analysis because of a positive test by PCR on the blood sample obtained at birth. Postnatal seroconversion to HIV-1 occurred in four of the five infants born to the mothers who seroconverted during the first 3 months post partum, and in four infants of the 10 mothers who seroconverted between month 4 and month 21. In all cases, the infant seroconverted during the same three-month period as the mother. The main risk factor for maternal seroconversion was being single.

CONCLUSIONS

HIV-1 infection can be transmitted from mothers to infants during the postnatal period. Colostrum and breast milk may be efficient routes for the transmission of HIV-1 from recently infected mothers to their infants.