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Human immunodeficiency virus type 1 (HIV-1) is transmitted mainly by cell-to-cell contact. We postulated that transmission of HIV-1 through breastmilk could be favoured by the presence of infected cells, by deficiency of anti-infective substances in breastmilk, or both factors. 215 HIV-1-infected women were enrolled at delivery in Kigali, Rwanda; milk samples were collected 15 days, 6 months, and 18 months post partum. HIV-1 IgG, secretory IgA, and IgM were assayed by western blot, for the latter two after removal of IgG with protein G. In the 15-day and 6-month samples, we sought viral genome in milk cells by a double polymerase chain reaction with three sets of primers (gag, pol, and env). HIV-1 infection in the offspring was defined according to serological and clinical criteria. At 15 days, 6 months, and 18 months post partum, HIV-1 specific IgG was detected in 95%, 98%, and 97% of breastmilk samples, IgA in 23%, 28%, and 41%, and IgM in 66%, 78%, and 41%. In children who survived longer than 18 months, the probability of infection was associated with lack of persistence of IgM and IgA in their mothers' milk (adjusted chi 2 for trend, p = 0.01 for IgM and p = 0.05 for IgA). The presence of HIV-1-infected cells in the milk 15 days post partum was strongly predictive of HIV-1 infection in the child, by both univariate (p0.05) and multivariate analysis (p = 0.01). The combination of HIV-1-infected cells in breastmilk and a defective IgM response was the strongest predictor of infection. HIV-1 infection in breastfed children born to infected mothers is associated with the presence of integrated viral DNA in the mothers' milk cells. IgM and IgA anti-HIV-1 in breastmilk may protect against postnatal transmission of the virus.

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.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.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.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.

In order to study the relation between human immunodeficiency virus (HIV) infection and malaria in women, during and after pregnancy, a prospective cohort study was initiated at the Centre Hospitalier de Kigali in Rwanda through routine voluntary and confidential HIV screening in antenatal clinics. At inclusion in the cohort of all HIV-positive and an equivalent number of HIV-negative pregnant women, between 21 and 28 weeks of gestation, sociodemographic characteristics and medical history during the current pregnancy were collected; screening for malaria (tick blood smear) and anemia and a CD4 lymphocyte count were systematically performed. Each woman enrolled had a monthly follow-up until 6 months after delivery. A clinic was implemented that was accessible and free of charge to every woman during the study period between scheduled visits. Malaria infection was systematically screened in case of fever or other compatible symptoms. The cohort included 228 HIV-positive and 229 HIV-negative women. At inclusion, malaria prevalence was 8.0% in HIV-positive women and 3.5% in HIV-negative women (P < 0.04). Over the study period, the incidence of malaria was 6.2 per 100 women-months in the HIV-positive group and 3.5 in the HIV-negative group (relative risk [RR] = 1.7, 95% confidence interval [CI] = 1.4-2.3). The bulk of the difference occurred postpartum. The Kaplan-Meier 9-month probability of remaining free of malaria infection was 51.8% in HIV-positive women and 65.2% in HIV-negative women (P = 0.013). When taking account in the same multivariate model (including HIV infection, primiparity, CD4 lymphocytes, anemia, and education level), positive HIV serostatus remained the only factor significantly associated with malaria infection (RR = 1.4, CI = 1.1-1.6; P = 0.016). Our study prospectively documents the association between malaria and maternal HIV infection and highlights the increased risk of malaria occurrence in all HIV-infected women. Strategies to reduce the malaria morbidity during pregnancy should be reinforced in areas of high HIV seroprevalence.

OBJECTIVE: To study the relationship between maternal plasma RNA levels and mother-to-child transmission (MTCT) of HIV-1 in African breastfed children. DESIGN: Nested case-control study within a randomized trial assessing the efficacy of a short maternal zidovudine (ZDV) regimen to reduce MTCT. METHODS: Eligible women received either 300 mg of ZDV twice a day until labour, 600 mg at the beginning of labour and 300 mg twice a day for 7 days post-partum or a placebo. The diagnosis of paediatric HIV-1 infection was based on PCR tests at days 1--8, 45, 90 and 180 then on serology performed at 3 monthl intervals. Plasma HIV-1 RNA was measured at inclusion and on day 8 after delivery for all women who did transmit HIV to their children (cases) using a Chiron branched DNA assay (sensitivity 50 copies/ml) and compared with women who did not transmit (two per case) matched for phase trial, treatment allocation and site. RESULTS: At inclusion, mean log10 viral load was 4.6 among 55 transmitting mothers and 3.7 among 117 non transmitters (P = 0.0001). Among transmitters, the mean difference in log10 viral load between day 8 post-partum and inclusion was -0.13 in the ZDV group (n = 23) versus 0.27 in the placebo group (n = 32; P = 0.01); among non transmitters it was -0.35 for the ZDV group (n = 47) versus 0.27 in the placebo group (n = 70; P < 10(-4)). In multivariate logistic regression analysis, odds ratios for MTCT were 8.7 (95% confidence interval, 3.7-20.6) for 1 log(10) increase of maternal RNA at inclusion and 4.2 (95% confidence interval, 1.7--10.3) for 1 log(10) increase difference from inclusion to day 8 post-partum. CONCLUSION: High maternal viral load at inclusion strongly predicts MTCT of HIV in Africa. A short ZDV treatment regimen decreases significantly maternal viral load from its pretreatment level.

Variation in HIV-1 genomic RNA was studied in seroconversion samples from mother–child pairs from a Rwandan cohort. The mothers ( n = 8) were heterosexually infected and their children ( n = 6) were vertically infected by breast milk. Five of the children seroconverted within the same 3-month period as did their mothers. Highly homogeneous subtype A V3 and p17 gag sequence populations were observed in three mother–child pairs, one of the two nontransmitting mothers, and one child (mean nucleotide distances 0 to 0.9%). Heterogeneous populations of subtype A V3 and p17 gag sequences were found in one mother and a mother–child pair (1.4 to 2.8% for V3, 1.0 to 1.9% for p17). The second nontransmitting mother was infected with a heterogeneous A V1-V3 /C p17-p24 recombinant virus population (3.8% for V3, 2.4% for p17). Finally, in one woman subtype C V3 sequences were observed, in addition to highly homogeneous subtype A V3 and p17 gag sequence populations, also found in the child. Coexistence of subtype A V1-V3 and C V1-V3 env sequences in the mother was confirmed in a follow-up sample. The gag gene of both the maternal and the child's virus population represented an A/C recombinant sequence (A p17 /C p24 ). An infection with subtype C V1-V3/p17-p24 was found upon testing of three additional participants of the mother–child cohort, indicating that subtype C is present in Rwanda. In conclusion, heterogeneity, coinfection, and intersubtype recombinants are not uncommon in primary HIV-1 infections in Rwanda.

The evolution of genomic RNA of human immunodeficiency virus type 1 (HIV-1), subtype A, was studied in three Rwandan mother-child pairs over a period of 12-30 months. In two pairs a homogeneous subtype A V3 sequence population was observed at seroconversion and the virus populations in the children resembled those in the mothers. One of these mother-child pairs was infected with an A/C recombinant virus (Ap17/Cp24). In the third pair, a heterogeneous V3 sequence population was observed in the maternal seroconversion sample but the V3 sequence population in the child's sample was homogeneous. In each individual the intra- and intersample variation (between the seroconversion and follow-up samples) increased over time in both the V3 region and p17gag. Independent evolution for 1-2 years did not abolish the epidemiological relationship between virus populations in mother and child.

Objective To compare the anthropometric characteristics of children with and without HIV-1 infection. Methods In a prospective cohort study of 218 children born to HIV-1 seropositive mothers and 218 children born to HIV-1 seronegative mothers in Kigali, Rwanda, 3 groups were compared: infected children (n = 46); uninfected children born to seropositive mothers (n = 140); and uninfected children born to seronegative mothers (n = 207). Weight, height and head circumference were measured at birth, every 3 months during the first year of life and every 6 months thereafter. The weight-for-age, height-for-age, weight-for-height and head circumference-for-age mean z scores were calculated. Results The weight-for-age, height-for-age and head circumference-for-age mean z scores were lower among HIV-infected children than among uninfected ones at each time period. The reduction in the weight-for-age mean z score was the greatest between 12 and 36 months. The reduction in the height-for-age mean z score of HIV-infected children was persistently below 2 SD after 9 months of age. On the other hand the weight-for-height mean z score was not consistently lower in HIV-infected children when compared with uninfected ones. The anthropometric characteristics of uninfected children born to seropositive mothers were similar to those of children born to seronegative mothers. Conclusions In this study HIV-infected children were more frequently stunted (low height-for-age) than uninfected ones. Wasting (low weight-for-height) was not common among HIV-infected children.

To estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda.Fixed prospective cohort followed for 36 months between November 1988 and June 1992, as part of an ongoing study of mother-to-child transmission of HIV-1.Centre Hospitalier, Kigali, Rwanda.A total of 216 HIV-seronegative women were enrolled at delivery between November 1988 and June 1989.A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. Incidence density rates of HIV seroconversion were estimated.The follow-up rate after 3 years was 89%, assessed by the maximum person-years method. The seroincidence density rate was 3.5 per 100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up. Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counselling, and the first 6-month postpartum effects on this estimate.This fixed cohort provided an overall estimation of the HIV infection incidence rate and its dynamics. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.The objective was to estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda. A fixed prospective cohort followed a total of 216 HIV-seronegative women for 36 months between November 1988 and June 1992 at Centre Hospitalier, Kigali, Rwanda. A study of mother-to-child transmission of HIV-1 has been going on at the Centre Hospitalier de Kigali since November 1988. A group of HIV-seronegative women matched by maternal age and parity was consecutively selected as a comparison group. The mean maternal age was 25.1 years (SD, 4.5 years), and the total number of pregnancies was 2.7 (SD, 1.8). A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. The follow-up rate after 3 years was 89.2% (577/646.75), assessed by the maximum person-years method. 20 seroconversions were documented during the first 36 months of follow-up among the 216 women seronegative at inclusion, yielding a cumulative incidence of 11.2%. The largest number of seroconversions (8/20; 40%) was observed in the first 6 months of the postpartum period. The seroincidence density rate was 3.5/100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up (P = 0.01). Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counseling, and the first 6-month postpartum effects on this estimate. The study confirms that pregnant women may represent a population in which the HIV seroincidence is high and concentrated in the immediate postpartum period. Pregnant women should become a potential target group for future large scale vaccination trials and programs with adequate follow-up. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.

The authors report the results of the first 2 years of follow-up of a prospective cohort study on the mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) and its determinants which started in November 1988 in Kigali Rwanda. The study sample consists of 218 newborns of 215 HIV-1 seropositive women matched to 218 newborns of 216 HIV-1 seronegative women of the same age and parity. They were followed every 2 weeks during the first 2 years of follow-up. HIV-1 antibodies were detected by enzyme-linked immunoabsorbent assay and Western blot at 3-month intervals. 2 methods of calculating the mother-to-child transmission rate were used: method 1 combines the information provided by the persistence of HIV-1 antibodies at 15 months of age in children born to HIV seropositive mothers and the excess mortality in this group compared with the cohort of children born to HIV seronegative mothers; method 2 is a case-by-case evaluation of all the children born to HIV seropositive mothers. A logistic regression model was used to study the determinants of transmission. The probability of survival at 24 months of age was 81% (95% confidence interval [CI] 75-86) in children born to seropositive mothers compared with 95% (95% CI 92-98) in children born to seronegative mothers (p < 0.001). The mother-to-child transmission rate calculated with method 1 was 25.7% (95% CI 18.8-32.5). With method 2 the medium estimate was 24.7%. In the multivariate analysis a CD4/CD8 ratio < 0.5 was the only maternal factor statistically associated with increased risk of mother-to-child transmission of HIV-1 (odds ratio = 2.9 95% CI 1.2-7.2). The authors findings present evidence for a higher mother-to-child transmission rate of HIV-1 in children born in Rwanda than in industrialized countries. (authors)