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

Predictors of maternal HIV acquisition during pregnancy and lactation in sub-Saharan Africa: A systematic review and narrative synthesis

OBJECTIVES

To eliminate vertical transmission of HIV, global institutions recommend using a risk-guided approach for HIV prevention services in antenatal and postnatal settings. Identifying predictors of maternal HIV acquisition can inform the development of risk-guided approaches, but individual studies of predictors can have limited power and generalizability.

METHODS

We conducted a systematic review and narrative synthesis to identify common predictors of maternal HIV acquisition in sub-Saharan Africa (SSA). We searched four databases for full-text articles that estimated associations between at least one predictor and risk of HIV acquisition among pregnant and/or lactating women (PLW) in SSA. We restricted our synthesis to predictors assessed in at least four study populations. For these predictors, we summarized how each predictor was defined and used vote counting and descriptive statistics to characterize overall trends.

RESULTS

We identified 26 eligible publications that summarized results from 24 unique studies. Studies were implemented in 12 countries between 1988 and 2021 and enrolled a total of 164,480 PLW at risk of acquiring HIV. Of the 66 predictors evaluated, 16 met our inclusion criteria. Estimated associations tended to be imprecise and variability in how predictors were measured precluded meta-analyses. We observed trends towards a higher risk of maternal HIV acquisition among young women and women who reported early coital debut, multiple partnerships, sexually transmitted infections, being unaware of partner HIV status, or having a partner living with HIV. In most studies, PLW in stable, monogamous relationships experienced a lower risk of acquiring HIV than those who were single, separated, or in a polygynous marriage. HIV risk perception, condom use, and vaginal drying were also commonly associated with HIV acquisition risk.

CONCLUSIONS

In our systematic review and narrative synthesis, we identified several easily measured characteristics that were associated with HIV acquisition among PLW in multiple study populations across SSA. Such findings can support the development and refinement of risk-guided approaches for HIV prevention in the region.

Pregnancy Among HIV-Serodiscordant Couples: Case Report of Vertical Transmission and Retrospective Case Series

BACKGROUND

HIV transmission during pregnancy and breastfeeding among serodiscordant heterosexual couples represents an ongoing barrier to the elimination of vertical transmission of HIV-1 infection in Canada.

OBJECTIVE

To report a case of vertical HIV transmission during breastfeeding and examine the prevalence of risk factors for HIV transmission in the pregnancy and postpartum periods among serodiscordant couples where the male partner is HIV positive and female partner HIV negative.

METHODS

Case report and retrospective chart review of HIV-serodiscordant pregnant couples over an eight-year period in Edmonton, Canada.

RESULTS

We report a case of maternal primary HIV infection during the postpartum period and vertical transmission to a nursing infant that went undetected until the infant presented with AIDS. We also report a series of 41 serodiscordant pregnant couples identified by our public health nurse between 2008 and 2016. Among HIV-infected male partners, 20 (49%) had a detectable viral load (VL) during their partner's pregnancy and during breastfeeding, with median peak VL 4,700 copies/mL (range 49-120,000) and 5,100 copies/mL (range 40-120,000) during pregnancy and breastfeeding, respectively. None of the female partners seroconverted during pregnancy, but three seroconverted at 1.8, 2.4, and 6.9 years after delivery. No vertical transmission occurred.

CONCLUSION

Despite concerted attempts to minimize HIV transmission during pregnancy and breastfeeding in our well-resourced setting, residual transmission risk remains due to non-suppressed viral load within many HIV-serodiscordant pregnant couples.

Sexuality and childbearing as it is experienced by women living with HIV in Sweden: a lifeworld phenomenological study

The effectiveness of antiretroviral treatment has reduced sexual HIV transmission and mother-to-child-transmission. To optimally support women living with HIV, health care providers need deepened knowledge about HIV, sexuality and childbearing. The aim of this study was to describe the phenomenon sexuality and childbearing as experienced by women living with HIV in Sweden. Data were collected by phenomenon-oriented interviews with 18 HIV-positive women. A reflective lifeworld analysis based on phenomenological philosophy was conducted, describing the meaning structure of the phenomenon. The essence of the phenomenon is that perceptions about HIV and its contagiousness profoundly influence sexual habits and considerations in relation to pregnancy and childbearing. These perceptions are formed in combination with knowledge and interpretations about HIV by the women themselves and by their environments. The essence is further described by its constituents: Risk of transmission imposes demands on responsibility; The contagiousness of HIV limits sexuality and childbearing; Knowledge about HIV transmission provides confident choices and decisions; and To re-create sexuality and childbearing. Although HIV has a low risk of transmission if being well treated, our study shows that HIV-positive women feel more or less contagious, which influences sexuality and decision-making in relation to become pregnant and give birth.

Pharmacogenetics of nevirapine excretion into breast milk and infants' exposure through breast milk versus postexposure prophylaxis

AIM

The influence of genetic factors on nevirapine (NVP) breast milk pharmacokinetics and breastfed infants' exposure were investigated.

PATIENTS & METHODS

Associations between nine SNPs in NVP disposition genes in mothers and its plasma and breast milk concentrations were explored in nursing mother-infant pairs.

RESULTS

NVP pharmacokinetics in maternal plasma, breast milk and infant exposure indices were influenced by CYP2B6 516G>T and 983T>C. The median (range) milk-to-plasma area under the curve (AUC0-12) ratio was 0.95 (0.56-1.5). Calculated as percentages of pediatric treatment, infant postexposure prophylaxis and maternal weight-adjusted doses, the maximum exposure indices were 3.64% (1.99-9.88), 26.0% (9.93-79.1) and 13.8% (5.77-27.7), respectively. Infant plasma concentration as a result of exposure through breast milk (n = 93), pre-exposure prophylaxis (n = 10) and both (n = 27) were 660 (104-3090), 1020 (401-3325) and 2720 ng/ml (1360-7290), respectively.

CONCLUSION

The clinical significance of the observed differences between routes of infants' exposure warrants further investigation.

HIV transmission through breastfeeding: still possible in developed countries

We describe here the case of a 13-month-old boy who acquired HIV infection postnatally through breastfeeding in a developed country in 2012. His mother had regular pregnancy follow-up and was found to be seronegative for HIV on 2 consecutive screening tests (during pregnancy and just after delivery). However, 1 year later, diagnosis of HIV infection arose in both of them after a pediatric emergency department visit for bronchitis when unexplained hepatosplenomegaly and inflammatory syndrome were noted. The negative maternal viral load found just after delivery confirmed that the mother's seroconversion occurred postnatally, which allowed for active HIV transmission during lactation and lack of the efficient preventive measures that have implemented in Belgium for years. We discuss this uncommon but still existing mode of HIV transmission in industrialized countries and highlight the importance of implementing new targeted health education interventions in addition to constant clinicians' awareness.

Incident HIV during pregnancy and postpartum and risk of mother-to-child HIV transmission: a systematic review and meta-analysis

BACKGROUND

Women may have persistent risk of HIV acquisition during pregnancy and postpartum. Estimating risk of HIV during these periods is important to inform optimal prevention approaches. We performed a systematic review and meta-analysis to estimate maternal HIV incidence during pregnancy/postpartum and to compare mother-to-child HIV transmission (MTCT) risk among women with incident versus chronic infection.

METHODS AND FINDINGS

We searched PubMed, Embase, and AIDS-related conference abstracts between January 1, 1980, and October 31, 2013, for articles and abstracts describing HIV acquisition during pregnancy/postpartum. The inclusion criterion was studies with data on recent HIV during pregnancy/postpartum. Random effects models were constructed to pool HIV incidence rates, cumulative HIV incidence, hazard ratios (HRs), or odds ratios (ORs) summarizing the association between pregnancy/postpartum status and HIV incidence, and MTCT risk and rates. Overall, 1,176 studies met the search criteria, of which 78 met the inclusion criterion, and 47 contributed data. Using data from 19 cohorts representing 22,803 total person-years, the pooled HIV incidence rate during pregnancy/postpartum was 3.8/100 person-years (95% CI 3.0-4.6): 4.7/100 person-years during pregnancy and 2.9/100 person-years postpartum (p = 0.18). Pooled cumulative HIV incidence was significantly higher in African than non-African countries (3.6% versus 0.3%, respectively; p<0.001). Risk of HIV was not significantly higher among pregnant (HR 1.3, 95% CI 0.5-2.1) or postpartum women (HR 1.1, 95% CI 0.6-1.6) than among non-pregnant/non-postpartum women in five studies with available data. In African cohorts, MTCT risk was significantly higher among women with incident versus chronic HIV infection in the postpartum period (OR 2.9, 95% CI 2.2-3.9) or in pregnancy/postpartum periods combined (OR 2.3, 95% CI 1.2-4.4). However, the small number of studies limited power to detect associations and sources of heterogeneity.

CONCLUSIONS

Pregnancy and the postpartum period are times of persistent HIV risk, at rates similar to "high risk" cohorts. MTCT risk was elevated among women with incident infections. Detection and prevention of incident HIV in pregnancy/postpartum should be prioritized, and is critical to decrease MTCT.

Infant feeding modes and determinants among HIV-1-infected African Women in the Kesho Bora Study

OBJECTIVE

To assess breastfeeding modes and determinants in a prevention of mother-to-child transmission study.

DESIGN

HIV-1-infected pregnant women from 5 sites in Burkina Faso, Kenya, and South Africa were enrolled in the study that comprised 2 prospective cohorts and 1 randomized controlled trial. Women were counseled to either breastfeed exclusively up to 6 months or formula feed from birth.

METHODS

Determinants of breastfeeding initiation and continuation by 3 months postpartum were investigated using multiple logistic regression analysis. Neonatal morbidity was defined as mother-reported fever, diarrhea, or vomiting during the first month of life.

RESULTS

Among 1028, 781 women (76%) initiated breastfeeding and 565 of 995 (56%) were still breastfeeding at 3 months postpartum (30% exclusively, 18% predominantly, and 8% partially). Study site (Durban, Mombasa, and Nairobi compared with Bobo-Dioulasso), CD4 cell count (<200 cells/mm), secondary schooling (compared with none), and emergency cesarean delivery (compared with vaginal delivery) were independently associated with a lower probability of ever breastfeeding. The odds of still breastfeeding by 3 months postpartum (among those breastfeeding by 1 month) were lower in Mombasa, Nairobi, and Somkhele (compared with Bobo-Dioulasso) and among infants with neonatal morbidity [0.60 (0.37-0.976)]. The odds of exclusive breastfeeding (EBF) by 3 months (if EBF by 1 month) were lower in Mombasa and Nairobi, in ill neonates [0.54 (0.31-0.93)] and boys [0.51 (0.34-0.77)].

CONCLUSIONS

EBF was of short duration, particularly for boys. The importance of neonatal morbidity for breastfeeding cessation requires further investigation. Infant feeding counseling might need adaptation to better support mothers of boys and ill neonates.

The contribution of maternal HIV seroconversion during late pregnancy and breastfeeding to mother-to-child transmission of HIV

BACKGROUND

The prevention of mother-to-child transmission (PMTCT) of HIV has been focused mainly on women who are HIV positive at their first antenatal visit, but there is uncertainty regarding the contribution to overall transmission from mothers who seroconvert after their first antenatal visit and before weaning.

METHOD

A mathematical model was developed to simulate changes in mother-to-child transmission of HIV over time, in South Africa. The model allows for changes in infant feeding practices as infants age, temporal changes in the provision of antiretroviral prophylaxis and counseling on infant feeding, as well as temporal changes in maternal HIV prevalence and incidence.

RESULTS

The proportion of mother-to-child transmission (MTCT) from mothers who seroconverted after their first antenatal visit was 26% [95% confidence interval (CI): 22% to 30%] in 2008, or 15,000 of 57,000 infections. It is estimated that by 2014, total MTCT will reduce to 39,000 per annum, and transmission from mothers seroconverting after their first antenatal visit will reduce to 13,000 per annum, accounting for 34% (95% CI: 29% to 39%) of MTCT. If maternal HIV incidence during late pregnancy and breastfeeding were reduced by 50% after 2010, and HIV screening were repeated in late pregnancy and at 6-week immunization visits after 2010, the average annual number of MTCT cases over the 2010-2015 period would reduce by 28% (95% CI: 25% to 31%), from 39,000 to 28,000 per annum.

CONCLUSION

Maternal seroconversion during late pregnancy and breastfeeding contributes significantly to the pediatric HIV burden and needs greater attention in the planning of prevention of MTCT programs.

Prenatal Screening for HIV in Nova Scotia: Survey of Postpartum Women and Audit of Current Prenatal Screening Practices

BACKGROUND

Current guidelines for screening for HIV infections in Nova Scotia recommend an opt-in approach in which patients are counselled and consent to testing. The objectives of the present study were to measure adherence to these recommendations, to explore women's knowledge, attitudes, beliefs and behaviours concerning HIV screening, and to compare these results with prenatal screening practices for rubella, hepatitis B and group B streptococcus.

METHODS

All women who gave birth consecutively during a seven-week period were recruited. Study participants were interviewed to determine their knowledge, attitudes and beliefs concerning prenatal screening. Hospital and laboratory records were reviewed for information concerning prenatal screening and perinatal treatment to audit screening practices.

RESULTS

A total of 279 patients were enrolled in the study, representing 58% of those eligible. The HIV screening rate was 72%, compared with 95% for rubella, 89% for hepatitis B and 24% for group B streptococcus. Of the participants tested for HIV, 80% were aware of being tested. Of all the study participants, 17% indicated having received pretest counselling about HIV, 56% volunteered to be tested for HIV, 78% received the test results, and 3.8% received post-test counselling. More participants preferred an opt-out approach to HIV screening (50%), where testing is routinely performed on everyone, rather than the opt-in approach (43%). Participants displayed a similar preference for screening for the other infections.

INTERPRETATION

HIV prenatal testing rates in Nova Scotia are comparable with those of other provinces that recommend an opt-in approach, but are lower than testing rates for opt-out programs. Most study participants were not screened using the recommended opt-in approach.

Intravaginal practices, bacterial vaginosis, and HIV infection in women: individual participant data meta-analysis

BACKGROUND

Identifying modifiable factors that increase women's vulnerability to HIV is a critical step in developing effective female-initiated prevention interventions. The primary objective of this study was to pool individual participant data from prospective longitudinal studies to investigate the association between intravaginal practices and acquisition of HIV infection among women in sub-Saharan Africa. Secondary objectives were to investigate associations between intravaginal practices and disrupted vaginal flora; and between disrupted vaginal flora and HIV acquisition.

METHODS AND FINDINGS

We conducted a meta-analysis of individual participant data from 13 prospective cohort studies involving 14,874 women, of whom 791 acquired HIV infection during 21,218 woman years of follow-up. Data were pooled using random-effects meta-analysis. The level of between-study heterogeneity was low in all analyses (I(2) values 0.0%-16.1%). Intravaginal use of cloth or paper (pooled adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.18-1.83), insertion of products to dry or tighten the vagina (aHR 1.31, 95% CI 1.00-1.71), and intravaginal cleaning with soap (aHR 1.24, 95% CI 1.01-1.53) remained associated with HIV acquisition after controlling for age, marital status, and number of sex partners in the past 3 months. Intravaginal cleaning with soap was also associated with the development of intermediate vaginal flora and bacterial vaginosis in women with normal vaginal flora at baseline (pooled adjusted odds ratio [OR] 1.24, 95% CI 1.04-1.47). Use of cloth or paper was not associated with the development of disrupted vaginal flora. Intermediate vaginal flora and bacterial vaginosis were each associated with HIV acquisition in multivariable models when measured at baseline (aHR 1.54 and 1.69, p<0.001) or at the visit before the estimated date of HIV infection (aHR 1.41 and 1.53, p<0.001), respectively.

CONCLUSIONS

This study provides evidence to suggest that some intravaginal practices increase the risk of HIV acquisition but a direct causal pathway linking intravaginal cleaning with soap, disruption of vaginal flora, and HIV acquisition has not yet been demonstrated. More consistency in the definition and measurement of specific intravaginal practices is warranted so that the effects of specific intravaginal practices and products can be further elucidated. Please see later in the article for the Editors' Summary.

Mother to child transmission of HIV among Zimbabwean women who seroconverted postnatally: prospective cohort study

OBJECTIVES

To estimate the rates and timing of mother to infant transmission of HIV associated with breast feeding in mothers who seroconvert postnatally, and their breast milk and plasma HIV loads during and following seroconversion, compared with women who tested HIV positive at delivery.

DESIGN

Prospective cohort study.

SETTING

Urban Zimbabwe.

PARTICIPANTS

14 110 women and infants enrolled in the Zimbabwe Vitamin A for Mothers and Babies (ZVITAMBO) trial (1997-2001).

MAIN OUTCOME MEASURES

Mother to child transmission of HIV, and breast milk and maternal plasma HIV load during the postpartum period.

RESULTS

Among mothers who tested HIV positive at baseline and whose infant tested HIV negative with polymerase chain reaction (PCR) at six weeks (n=2870), breastfeeding associated transmission was responsible for an average of 8.96 infant infections per 100 child years of breast feeding (95% CI 7.92 to 10.14) and varied little over the breastfeeding period. Breastfeeding associated transmission for mothers who seroconverted postnatally (n=334) averaged 34.56 infant infections per 100 child years (95% CI 26.60 to 44.91) during the first nine months after maternal infection, declined to 9.50 (95% CI 3.07 to 29.47) during the next three months, and was zero thereafter. Among women who seroconverted postnatally and in whom the precise timing of infection was known (≤90 days between last negative and first positive test; n=51), 62% (8/13) of transmissions occurred in the first three months after maternal infection and breastfeeding associated transmission was 4.6 times higher than in mothers who tested HIV positive at baseline and whose infant tested HIV negative with PCR at six weeks. Median plasma HIV concentration in all mothers who seroconverted postnatally declined from 5.0 log(10) copies/mL at the last negative enzyme linked immunosorbent assay (ELISA) to 4.1 log(10) copies/mL at 9-12 months after infection. Breast milk HIV load in this group was 4.3 log(10) copies/mL 0-30 days after infection, but rapidly declined to 2.0 log(10) copies/mL and <1.5 log(10) copies/mL by 31-90 days and more than 90 days, respectively. Among women whose plasma sample collected soon after delivery tested negative for HIV with ELISA but positive with PCR (n=17), 75% of their infants were infected or had died by 12 months. An estimated 18.6% to 20.4% of all breastfeeding associated transmission observed in the ZVITAMBO trial occurred among mothers who seroconverted postnatally.

CONCLUSIONS

Breastfeeding associated transmission is high during primary maternal HIV infection and is mirrored by a high but transient peak in breast milk HIV load. Around two thirds of breastfeeding associated transmission by women who seroconvert postnatally may occur while the mother is still in the "window period" of an antibody based test, when she would test HIV negative using one of these tests. Trial registration Clinical trials.gov NCT00198718.

Intravaginal practices, vaginal infections and HIV acquisition: systematic review and meta-analysis

BACKGROUND

Intravaginal practices are commonly used by women to manage their vaginal health and sexual life. These practices could, however, affect intravaginal mucosal integrity. The objectives of this study were to examine evidence for associations between: intravaginal practices and acquisition of HIV infection; intravaginal practices and vaginal infections; and vaginal infections and HIV acquisition.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a systematic review of prospective longitudinal studies, searching 15 electronic databases of journals and abstracts from two international conferences to 31(st) January 2008. Relevant articles were selected and data extracted in duplicate. Results were examined visually in forest plots and combined using random effects meta-analysis where appropriate. Of 2120 unique references we included 22 publications from 15 different studies in sub-Saharan Africa and the USA. Seven publications from five studies examined a range of intravaginal practices and HIV infection. No specific vaginal practices showed a protective effect against HIV or vaginal infections. Insertion of products for sex was associated with HIV in unadjusted analyses; only one study gave an adjusted estimate, which showed no association (hazard ratio 1.09, 95% confidence interval, CI 0.71, 1.67). HIV incidence was higher in women reporting intravaginal cleansing but confidence intervals were wide and heterogeneity high (adjusted hazard ratio 1.88, 95%CI 0.53, 6.69, I(2) 83.2%). HIV incidence was higher in women with bacterial vaginosis (adjusted effect 1.57, 95%CI 1.26, 1.94, I(2) 19.0%) and Trichomonas vaginalis (adjusted effect 1.64, 95%CI 1.28, 2.09, I(2) 0.0%).

CONCLUSIONS/SIGNIFICANCE

A pathway linking intravaginal cleaning practices with vaginal infections that increase susceptibility to HIV infection is plausible but conclusive evidence is lacking. Intravaginal practices do not appear to protect women from vaginal infections or HIV and some might be harmful.

Herpes simplex virus type 2 infection among young uncircumcised men in Kisumu, Kenya

OBJECTIVES

To identify factors associated with herpes simplex virus type 2 (HSV-2) infection among men aged 18-24 in Kisumu, Kenya.

METHODS

Baseline data from a randomised trial of male circumcision were analysed. Participants were interviewed for sociodemographic and behavioural risks. The outcome was HSV-2 by antibody status. Risk factors were considered singly and in combination through logistic regression models.

RESULTS

Among 2771 uncircumcised men, 766 (27.6%; 95% confidence interval (CI) 26.0% to 29.3%) tested antibody positive for HSV-2. The median age at first sex was 16 years, and the median number of lifetime sexual partners was four. HSV-2 seroprevalence increased from 19% among 18-year-olds to 43% among 24-year-olds (p<0.001). In multivariable analysis, statistically significant risks for infection were increasing age (adjusted odds ratio (AOR) = 1.22-2.58), being married or having a live-in female partner (AOR = 1.80; 95% CI 1.28 to 2.53), preferring "dry" sex (AOR = 1.39; 95% CI 1.14 to 1.69), reported penile cuts or abrasions during sex (AOR = 1.58; 95% CI 1.32 to 1.91), increasing lifetime sex partners (multiple response categories; AORs ranging from 1.65 to 1.97), and non-student occupation (multiple response categories; AORs ranging from 1.44 to 1.93). Risk decreased with reported condom used at last sex (AOR = 0.82; 95% CI 0.68 to 0.99).

CONCLUSION

Primary prevention efforts should be initiated at an early age. The same behavioural interventions used currently for HIV prevention-abstinence, reducing the number of sex partners and increasing condom use-should be effective for HSV-2 prevention.

Anal and dry sex in commercial sex work, and relation to risk for sexually transmitted infections and HIV in Meru, Kenya

OBJECTIVE

To examine the practices of anal intercourse and dry sex within a cohort of female sex workers (FSWs) in Kenya, focusing on the prevalence and perceived risk of the practices, demographic and behavioural correlates, and association with sexually transmitted infections (STI).

METHODS

A survey was conducted among FSWs in Meru, Kenya, with 147 participants randomly sampled from an existing cohort of self identified FSWs.

RESULTS

40.8% of participants reported ever practising anal intercourse and 36.1% reported ever practising dry sex. Although the majority of women surveyed believed anal intercourse and dry sex to be high risk practices for HIV infection compared with vaginal sex, about one third of women reported never or rarely using condoms during anal intercourse, and about 20% never or rarely using condoms during dry sex. Reported consistent condom use was lower with both of these practices than with penile-vaginal intercourse. Anal intercourse was associated with experience of recent forced sexual intercourse, while dry sex was not. Anal intercourse was almost always initiated by clients, whereas dry sex was likely to be initiated by the women themselves. Sex workers reported charging higher fees for both practices than for vaginal intercourse. Both practices were associated with reported symptoms and diagnoses of STI.

CONCLUSIONS

Both anal intercourse and dry sex were common in this sample, and although perceived as high risk practices, were not adequately protected with condom use. Education and other interventions regarding these high risk sexual behaviours need to be translated into safer practices, particularly consistent condom use, even in the face of financial vulnerability.

Distinguishing the temporal association between women's intravaginal practices and risk of human immunodeficiency virus infection: a prospective study of South African women

Cross-sectional studies have suggested that intravaginal practices, such as douching or "dry sex," may increase women's susceptibility to infection with human immunodeficiency virus (HIV). The authors examined the temporal nature of this association in a cohort of South African women. At enrollment (2001-2002), 4,089 women were tested for HIV infection. Participants reported their intravaginal practices at a 6-month follow-up visit and were followed with repeat HIV testing for up to 24 months. Among the 3,570 women who were HIV-negative at enrollment, 26% reported some type of intravaginal practice, mostly washing inside the vagina with water and/or cloth as part of daily hygiene. During follow-up, 85 incident HIV infections were observed. Intravaginal practices were associated with prevalent HIV at enrollment (adjusted odds ratio = 1.50, 95% confidence interval: 1.22, 1.85), but during follow-up there was no association between intravaginal practices and incident HIV (adjusted hazard ratio = 1.04, 95% confidence interval: 0.65, 1.68). These findings may be explained by a reversal of the causal sequence assumed for this association, since intravaginal practices may be undertaken in response to vaginal infections that occur more commonly among HIV-infected women. Intravaginal practices appear unlikely to be a cofactor in the male-to-female transmission of HIV in this setting.

Intravaginal practices, bacterial vaginosis, and women's susceptibility to HIV infection: epidemiological evidence and biological mechanisms

Intravaginal practices such as "dry sex" and douching have been suggested as a risk factor that may increase women's susceptibility to HIV infection. These behaviours appear common in different populations across sub-Saharan Africa, where practices include the use of antiseptic preparations, traditional medicines, or the insertion of fingers or cloths into the vagina. We systematically review the evidence for the association between women's intravaginal practices and HIV infection. Although a number of cross-sectional studies have shown that prevalent HIV infection is more common among women reporting intravaginal practices, the temporal nature of this association is unclear. Current evidence suggests that bacterial vaginosis, which is a likely risk factor for HIV infection, may be a mediator of the association between intravaginal practices and HIV. Although biologically plausible mechanisms exist, there is currently little epidemiological evidence suggesting that intravaginal practices increase women's susceptibility to HIV infection. Further research into factors that increase women's susceptibility to HIV will help to inform the design of vaginal microbicides and other HIV prevention interventions.

Breastfeeding and HIV

Breastfeeding is a route of HIV transmission from an HIV-infected mother to her infant. However, breastfeeding is an important pillar of child survival and the ideal way of feeding an infant, as well as providing a unique biological and emotional basis for child development. This chapter will highlight the dilemma created by the risks and benefits of breastfeeding and will discuss factors which increase the risk of HIV transmission during breastfeeding, as well as strategies which could be employed to reduce these risks. The research agenda is very full as many questions still remain unanswered.

Intravaginal Practices, HIV and Other Sexually Transmitted Diseases Among South African Women

BACKGROUND AND OBJECTIVES

Intravaginal practices, including wiping, douching, or inserting substances into the vagina, have been hypothesized to increase women's risk of HIV infection. However, data on the prevalence of these practices, and associations with HIV and other sexually transmitted diseases (STD), are limited.

STUDY DESIGN

We interviewed 2,897 women participating in a gynecologic screening study in Cape Town, South Africa, about their intravaginal practices. After clinical examination, cervical and blood samples were collected and tested for HIV and other STD [corrected].

RESULTS

Of the 831 (29%) women reporting some type of intravaginal practice, 48% reported using only water and cloth to clean inside the vagina, whereas 17% reported using antiseptics or detergents. Most women (53%) reported practices as part of regular hygiene. Intravaginal practices were strongly associated with behavioral risk factors, and recent multiple sexual partners [corrected]. Intravaginal practices were associated with prevalent HIV infection (adjusted odds ratio, 1.74; 95% confidence interval, 1.37-2.20), but were not associated with other STDs.

CONCLUSION

Prospective studies that include detailed measurements of correlated sexual risk behaviors are required to discern whether this association is causal in nature; if so, these behaviors could represent an important area for future HIV prevention interventions.

Human milk, breastfeeding, and transmission of human immunodeficiency virus type 1 in the United States. American Academy of Pediatrics Committee on Pediatric AIDS

Transmission of human immunodeficiency virus type 1 (HIV-1) through breastfeeding has been conclusively demonstrated. The risk of such transmission has been quantified, the timing has been clarified, and certain risk factors for breastfeeding transmission have been identified. In areas where infant formula is accessible, affordable, safe, and sustainable, avoidance of breastfeeding has represented one of the main components of mother-to-child HIV-1 transmission prevention efforts for many years. In areas where affordable and safe alternatives to breastfeeding may not be available, interventions to prevent breastfeeding transmission are being investigated. Complete avoidance of breastfeeding by HIV-1-infected women has been recommended by the American Academy of Pediatrics and the Centers for Disease Control and Prevention and remains the only means by which prevention of breastfeeding transmission of HIV-1 can be absolutely ensured. This technical report summarizes the information available regarding breastfeeding transmission of HIV-1.

HIV transmission through breastfeeding: problems and prevention

The greatest burden of HIV infection in women and their children is disproportionately borne by the poorest countries, especially in sub-Saharan Africa. Breastfeeding is a major health-promoting factor for infants and children in developing countries but the risk of mother-to-child transmission (MTCT) of HIV by this route is challenging traditional practices and health policies in low-resource countries. Maternal and infant factors contributing to the risk of MTCT through breastfeeding are still poorly understood and not well researched. Factors identified include: advanced clinical stages of infection in the mother; high maternal plasma HIV-1 load; presence of mastitis; and infant oral thrush. In many developing countries, international agencies are providing support and recommendations for preventing MTCT of HIV-1 by breastfeeding. Preventive strategies supported by WHO/UNICEF and charitable agencies in some sentinel centres in sub-Saharan Africa include routine antenatal voluntary counselling and testing (VCT), PCR testing of infants of seropositive mothers at 6 weeks of age, various combinations of a shortened period (3-6 mths) of exclusive breastfeeding, perinatal administration of antiretrovirals (ARV) such as nevirapine and provision of affordable and safe infant replacement feeds (presently given free by UNICEF in some centres). Many problems, however, have hindered effective implementation of these interventions. In many poor communities, even where VCT facilities are available, acceptance of HIV testing is low because there is fear of stigmatisation by the spouse, family or community and compliance with complex drug regimens is therefore poor. Other problems include the exorbitant cost of antiretroviral drugs, inadequately resourced health care systems and unavailability or poor acceptance of safe breast-milk alternatives. The rate of mixed feeding is high and so the risk of MTCT is increased. Continued promotion of exclusive breastfeeding for at least 6 months, irrespective of HIV status, followed by a properly prepared, high energy, nutritious complementary diet, with the possibility of early weaning to an animal milk formula, still appears to be the most appropriate option for the poor in countries with high levels of MTCT not deriving any benefit from the above strategies. While a longer period of breastfeeding would probably increase the risk of MTCT in vulnerable communities, a shorter duration would certainly increase infant morbidity and mortality. Results of investigations of the efficacy of ARV for protecting the infants of HIV-infected mothers during the breastfeeding period are awaited.

Is breast not best? Feeding babies born to HIV-positive mothers: bringing balance to a complex issue

Breastfeeding prevents millions of infant deaths each year throughout the world but causes at least one-third of all pediatric HIV infections. The first randomized trial of breastfeeding versus formula feeding, reported from Nairobi in March 2000, demonstrated an improved outcome for babies of highly selected HIV-positive mothers assigned to formula feed. However, several conditions must be in place and accepted before such replacement feeding can increase HIV-free survival. The proportion of sub-Saharan African women who have access to and will accept these conditions is small. In the short term, efforts to make breastfeeding safer will probably benefit a greater number of African babies.

[Breastfeeding and hepatitis C virus (HCV): the need for a careful appraisal]

We review the available data on the possible role of breast-feeding in hepatitis C virus (HCV) transmission to infants of HCV-RNA-positive mothers. Current knowledge about HCV excretion through breast milk, HCV infection of breast-fed infants by mothers contaminated after delivery, and vertical transmission risk to infants breast-fed by chronic HCV viremic mothers are presented. Vertical transmission risk by breast-feeding HCV-RNA-positive mothers is unclear: no study has been performed with the aim and the required methodology to evaluate HCV transmission risk related to breast-feeding duration. Recommendations to HCV-RNA-positive mothers who wish to breast-feed their infant are discussed in light of present knowledge about HCV secretion in breast milk, mother-to-infant HCV transmission, and historical records on vertical transmission of other viruses to infants breast-fed by their viremic mothers.

Clinical care issues for women living with HIV and AIDS in the United States

As the number of women infected with HIV in the United States continues to increase, the medical community is faced with the challenge of providing adequate and appropriate care to them. This paper reviews key questions concerning the state of knowledge on the epidemiology, biology, and clinical care of women living with HIV and AIDS in the United States. Because heterosexual transmission accounts for a growing number of cases among women, biological factors and cofactors that may enhance women's susceptibility to HIV infection are also reviewed. HIV-related gynecological issues are presented separately to evaluate whether gynecological complications are distinct in HIV-uninfected and HIV-infected women. Questions of whether there are sex-specific differences in the efficacy and adverse effects of new antiviral agents are discussed. In addition, significant gaps are highlighted that still exist in our understanding of both the effects of HIV and HIV-related drugs upon pregnancy. Finally, the psychiatric stresses and complications that affect women living with HIV and AIDS are also discussed. In each section of this review, gaps in our knowledge of these issues are identified. To properly address these disparities in knowledge, not only do efforts to gather sex-specific biomedical data need to be more exacting, but there is a distinct need to conduct more sex-specific research concerning HIV.

The dilemma of postnatal mother-to-child transmission of HIV: to breastfeed or not?

The promotion of nearly universal breastfeeding has played an important role in improving child health by providing optimum nutrition and protection against common childhood infections, and by promoting child spacing. Unfortunately, it has become clear that breastfeeding is responsible also for much of the increasing burden of worldwide pediatric human immunodeficiency virus (HIV) infection, especially in the developing nations (12-14% additional risk of HIV infection transmitted by breastfeeding; 35% total proportion of all HIV-infected children in an area infected through breastfeeding). Several factors influence the transmission of HIV by breastfeeding, including whether a woman acquires her infection during breastfeeding (29% risk of transmission) or before pregnancy (7-10% risk of breastfeeding transmission),the degree of maternal plasma and breastmilk viral load, and the presence of mastitis. In areas of the world where adequate sanitary replacement feeding is not available, the decision to withhold breastfeeding so as to decrease HIV transmission may lead to increased rates of child morbidity and mortality from diarrheal and respiratory diseases, and malnutrition. This review summarizes current data on the pathophysiology of breastfeeding transmission of HIV infection, the risk factors for and incidence rates of transmission, and the feasibility of possible alternatives to exclusive breastfeeding in the setting of maternal HIV infection. Clearly, women must be fully informed about the risks of breastfeeding transmission of HIV, the risks of morbidity and mortality among nonbreastfed infants, and the expense and availability of procuring adequate replacement formula. If an uninterrupted access to a nutritionally adequate breastmilk substitute that can be safely prepared is ensured (as is possible in industrialized countries), HIV-infected women should be counseled not to breastfeed their infants.

Effect of intravaginal practices on the vaginal and cervical mucosa of Zimbabwean women

OBJECTIVES

Lesions on the vaginal and cervical mucosa may facilitate transmission of HIV and other sexually transmitted diseases (STDs). We evaluated the relationship between intravaginal practices and the presence of colposcopic lesions in Zimbabwean women.

METHODS

Users and nonusers of intravaginal practices were seen at enrollment, and at 1 and 6 months. Interviewing, counseling, and pelvic and colposcopic examinations were performed at each study visit. Specimens were collected at enrollment and 6 months.

RESULTS

Colposcopic lesions were found at least once in 83% of the participants (n = 162), and in 66% of all exams (n = 430). Most lesions were classified as related to infection with human Papillomavirus (HPV) (58%) or another pathogen (20%), but 11% of lesions could have been caused by intravaginal practices (signal lesions). Intravaginal practices were not associated with an increased incidence in signal lesions (95 and 124 lesions per 100 person-years of follow-up for users and nonusers respectively; p = .290), nor with the presence of signal lesions in multivariate baseline (odds ratio [OR], 1.32; 95% confidence interval [CI], 0.37-4.72; p = .666) and six month transition models (OR, 1.67; 95% CI, 0.59-4.70; p = .333).

CONCLUSIONS

No associations between intravaginal practices and colposcopic lesions were found in this study. However, the potential effect of intravaginal practices on the cervical and vaginal mucosa, and on subsequent HIV and STD transmission, warrants further study. The usefulness of colposcopy as a research tool in areas with high prevalences of HIV and HPV is questioned.

Traditional intravaginal practices and the heterosexual transmission of disease: a review

OBJECTIVE

To review reports on the use and effects of traditional intravaginal substances and practices.

METHOD

The medical and social science literature of the past 50 years regarding use and effects of traditional intravaginal substances and practices is reviewed.

RESULTS

Traditional intravaginal practices have been described in 11 countries of sub-Saharan Africa, and also in Qatar, Indonesia, Thailand, Haiti, the Dominican Republic, and the United States. Women's reasons for the practices include personal hygiene, disease prevention or treatment, and enhancement of sexual experience. Few studies document damage to the vaginal epithelium or changes in vaginal flora due to these practices. No prospective studies link these practices to disease transmission.

CONCLUSION

The determination of how these practices affect disease transmission will require precise definition of independent variables, which is difficult because of the diversity of the practices. It is appropriate to search for intervening variables; specifically, the effects on the vaginal pH, flora, and epithelium.

Management of HIV-infected children in the home and institutional settings. Care of children and infections control in schools, day care, hospital settings, home, foster care, and adoption

The likelihood of high-risk pediatric exposure to HIV infection, other than perinatal exposure, has been shown to be low in most cases, and HIV PEP should be considered on a case-by-case basis. Generic considerations in the management of children who have become HIV infected emphasizes the principles of inclusion, maintaining confidentiality of a child's HIV status, and notifying those who need to know about the HIV status to care properly for the child or adolescent. Although appropriate infection-control precautions are applicable for all children and for many pathogens, children especially HIV-infected children, exposed to such pathogens, must be managed in a timely fashion. In many cases, recommendations that are applicable in one setting are applicable in others. Some exceptions apply, including infection-control precautions in hospitals versus other settings. A few additional considerations have been made for special settings and activities, including adoption, foster care, athletics, summer camp, and other recreational activities.

Heterosexual anal intercourse: prevalence, cultural factors, and HIV infection and other health risks, Part I

Studies of heterosexual HIV transmission have consistently found anal intercourse to be a highly predictive risk factor for seroconversion. Yet most AIDS prevention messages targeted at heterosexuals, presumably influenced by cultural taboos against acknowledging this sexual practice, continue to emphasize vaginal and, increasingly, oral sex transmission. The health risks of anal sex appear to be severely underestimated by a substantial proportion of sexually active women and men in North and Latin America as well as parts of South Asia, Africa, and other regions. Among heterosexuals reported rates of condom use are nearly universally lower for anal than for vaginal intercourse. This review examines anal sex among the general population, including its prevalence in various world regions, related sociocultural factors, and other associated health problems including anorectal STDs, Hepatitis B infection, and HPV-related anal cancer in women. U.S. survey and other data suggest that, in terms of absolute numbers, approximately seven times more women than homosexual men engage in unprotected receptive anal intercourse. Research among higher risk subpopulations, including bisexual men, injecting drug users, female sex workers, inner-city adolescents, and serodiscordant heterosexual couples, indicates that persons particularly at risk of being infected by or transmitting HIV are also more likely to practice anal sex. Considering this finding, along with the much greater efficiency for HIV infection as well as lower rates of condom usage, a significant proportion of heterosexual transmission in some populations is due to anal intercourse. This typically stigmatized and hidden sexual practice must be given greater emphasis in AIDS/STD prevention, women's care, and other health promotion programs.

The practice and prevalence of dry sex among men and women in South Africa: a risk factor for sexually transmitted infections?

OBJECTIVES

To establish the prevalence of "dry sex" practice in a South African periurban population. To investigate the reasons for and factors influencing the practice of dry sex and to evaluate dry sex practice as a risk factor for sexually transmitted disease (STD).

DESIGN

Cross sectional sample survey.

METHODS

A random community sample of men and women aged between 16 and 35 in Gauteng Province, South Africa, were interviewed regarding the practice of dry sex using a structured interviewer administered questionnaire.

RESULTS

Dry sex practices were reported by 60% of men and 46% of women. Among younger individuals dry sex practice is far more common among the less educated, but there was no significant difference between education groups in the older respondents. A higher proportion of men practising dry sex than not practising dry sex reported having a past history of STD infection (56% versus 41%) although this difference was only marginally significant (p = 0.05). There was no difference in reported history of STD between women who practised dry sex and those who did not.

CONCLUSIONS

This study shows that dry sex practice is common in this community. The younger less educated group were the most likely to practise dry sex. Dry sex practice was associated with an increased prevalence of self reported STDs in men but not in women.

Sexual behaviour and risk assessment of HIV seroconvertors among urban male factory workers in Zimbabwe

Despite extensive HIV prevention programmes and knowledge of people dying of AIDS, people in Zimbabwe continue to be infected with HIV and other sexually transmitted infections (STIs). This paper presents selected case histories from interviews with 57 men who became HIV positive during follow up of 1678 seronegative male factory workers in Harare, and describes the circumstances in which they were exposed to infection. Youth was a major risk factor, with 47% of those who seroconverted aged between 18 and 24 yr. STIs were reported by 23% of the group in the seroconversion period, a marker of unprotected sex. Individuals did not recognise themselves or their partners as candidates for infection because of categorisation of high risk groups as "promiscuous" or clients of sex workers. Many were optimistic that they had changed sufficiently by using condoms more often or by avoiding sex workers. They made inaccurate assessments of who was safe for unprotected sex, based on judgements about their character, background and age. Over 40% of the seroconvertors had previously been counselled on staying HIV negative. Community approaches which nurture development of supportive group norms, respect for human rights and responsibilities, and safe environments for disclosure of HIV status, are vital for overcoming denial of risk at individual and societal levels. Special efforts targeted at youth are crucial since they have the highest risk of new infections and include use of media, drama, role models, advisory centres, peer education programmes. Health professionals need training and skills to enable people at risk of HIV infection to devise strategies based on more realistic personal risk assessment.

Infant feeding and risk of mother-to-child transmission of HIV-1 in São Paulo State, Brazil. São Paulo Collaborative Study for Vertical Transmission of HIV-1

Although vertical transmission of HIV-1 can occur through breast-feeding, little is known about the effect of colostrum, duration of breast-feeding, mixing feeding, and nipple pathology. We used retrospective cohort data to examine the association between breast-feeding-related factors and transmission of HIV-1 from mother to child in São Paulo State, Brazil. Information on maternal and postnatal factors was collected by medical record review and interview. Infection status was determined for 434 children by anti-HIV-1 tests performed beyond 18 months of age or diagnosis of AIDS at any age. Among 168 breast-fed children, the risk of transmission of HIV-1 was 21%, compared with 13% (p = .01) among 264 children artificially fed. Breast-feeding was independently and significantly associated with mother-to-child transmission of HIV-1 after controlling for stage of maternal HIV-1 disease (odds ratio [OR] = 2.2; 95% confidence interval [CI], 1.3-3.8). A trend was shown toward an increased risk of transmission with longer duration of breast-feeding, a history of bleeding nipples, and introduction of other liquid food before weaning, but these associations were not statistically significant. History of colostrum intake or cracked nipples without bleeding were not associated with transmission. Most of the women who breast-fed were unaware of their HIV-1 infection status at the time of delivery. Avoidance of mixed feeding and withholding of breast-feeding in the presence of bleeding nipples should be considered in further research as strategies to reduce postnatal transmission of HIV-1 in settings in which safe and sustainable alternatives for breast-feeding are not yet available.

Mother-to-child transmission of HIV-1

After reviewing the evidence on the relation of vertical transmission of HIV to stage of infection in the mother, I developed a stochastic model of transmission in which the probability of transmission per week is proportional to the virus load in the mother. The virus load in different stages of the infection is measured by viral RNA levels or tissue culture infectious virus levels in plasma. The constant of proportionality is assumed to be different for transmission during pregnancy, during parturition, and during breast-feeding. Using data on transmission from mothers who are in the primary stage of infection, I estimated the constant of proportionality and calculated the probability of transmission during pregnancy as a function of the time pregnancy starts in relation to the stage of the infection. For breast-feeding, I calculated the conditional probability of transmission by breast-feeding for 20 weeks, dependent on the infant escaping infection during pregnancy and parturition. As might be expected, the probabilities of transmission are highest if the mother is in the primary stage of infection or in late stages of the disease and is quite low when the mother is in the asymptomatic stage of the infection.

HIV in the neonate

Mother-to-infant transmission of human immunodeficiency virus (HIV) is a worldwide problem. Between 7 and 40% of infants born to HIV-positive mothers become infected. The prognosis of these infants is poor, with most developing early and rapidly progressive disease. A number of advances in diagnosis and therapy offer opportunities to reduce the rate of vertical transmission and to improve the outlook of infected infants. Antiretroviral therapy during pregnancy and the neonatal period can markedly reduce the risk of mother-to-infant transmission. Recognition that 50% or more of infections are transmitted peripartum offers scope to further reduce the rate of transmission. However there is currently no consensus on the optimal management of pregnancy in HIV-infected women, and there is an urgent need for large randomized controlled trials. The development of polymerase chain reaction and p24 antigen assays has greatly facilitated the diagnosis of neonatal HIV infection, thereby enabling earlier supportive and anti-retroviral therapy. The place of zidovudine in paediatric HIV infection is now well-established, but the future will undoubtedly bring combination anti-retroviral therapy. Optimism about the prospects for developments in the prevention and treatment of paediatric acquired immunodeficiency syndrome must be tempered by the fact that the majority of cases occur in countries where patients have little or no access to medical care.

Unnatural constituents of breast milk--medication, lifestyle, pollutants, viruses

It is well recognised that although nutritionally breast milk is the optimal food for babies, there are a number of caveats to this, based on the consequences of the modern lifestyle. Here we have considered ways in which the young breast fed child may be exposed to various environmental and medical contaminants which might cause adverse reactions and to which he/she may not otherwise be exposed. These substances are divided into four different areas: (i) medication taken by the mother; (ii) exposure to possibly addictive drugs taken by the mother; (iii) exposure to pollutants mainly from the maternal diet or as the result of her occupation; (iv) viruses. The infant who consumes breast milk may be exposed to a variety of chemicals which may have untoward effects on his/her immediate health and temperament and future development. Potentially hazardous substances ingested by the breast fed infant include medicaments (or their metabolites) that may have been ingested by the mother, potentially addictive common neurotoxicants such as nicotine, caffeine and alcohol, illicit drugs such as heroin and cocaine, and pollutants such as polychlorinated biphenyls and dichlorodiphenyltrichloroethane (DDT). There is a paucity of good information on which to base reliable estimates of the harm that this may cause the child. Although breast feeding is known to protect against bacterial infection, a number of viruses are excreted in the breast milk which may infect the child asymptomatically (e.g. cytomegalovirus, Epstein-Barr virus) and which are not known to be harmful, as well as human immunodeficiency virus (HIV) excretion which, in contrast, does appear to increase the risk of the child becoming infected. Balancing the risk of infection to the child born to an HIV infected mother, results in the proposition that known HIV positive women in developing countries (where the risk of gastrointestinal infection is high) should continue to breast feed but those in the developed world (where the risk of gastrointestinal infection is lower) are better advised to bottle feed.

Breast-feeding and human immunodeficiency virus

Breast-feeding provides nutritional, immunological, and psychological benefits. It protects children from mortality and morbidity associated with diarrheal diseases, pneumonia and other infections. Breast feeding has also been shown to prolong the interval between births and thereby improve child survival and maternal health. However, studies suggest that in certain populations, breast feeding may account for nearly 14% of perinatal human immunodeficiency virus type 1 (HIV-1) transmission. It is therefore important that the risk of HIV-1 infection through breast feeding be weighed against the morbidity and mortality associated with bottle feeding. This paper discusses the literature dealing with breast feeding in women with HIV-1 infection. Specifically, the review addresses the issues surrounding infant mortality in areas of different HIV-1 prevalence where breast-feeding or bottle-feeding may be employed. Analysis suggests that the benefits of breast-feeding or bottle-feeding may be employed. Analysis suggests that the benefits of breast-feeding can substantially outweigh the putative risk of HIV-1 transmission unless the prevalence of HIV-1 infection is high or the difference in mortality between breast-fed and bottle-fed infants is very low.

Human immunodeficiency virus infection transmitted through breast milk

Perinatal acquisition of human immunodeficiency virus is responsible for most cases of pediatric AIDS. Breast feeding has been found to carry a higher risk of transmission of HIV and is not recommended to HIV infected mothers in the western world. In our country we have to be aware of the increasing incidence of pediatric AIDS and the varied constellation of symptoms it can present with. Also, we have to ensure that safe blood is available to avoid transfusion acquired diseases.

Patterns of sexual behaviour in a rural population in north-western Tanzania

The HIV epidemic in sub-Saharan Africa has been characterised by the predominance of heterosexual transmission. Patterns of sexual behaviour have been implicated in the spread of the epidemic, but few quantitative data are available on sexual behaviour in rural populations in Africa. This paper reports data from a survey of 1117 adults aged 15-54 years selected randomly from twelve rural communities in Mwanza Region, Tanzania. Sexual debut occurred early, 50% of women and 46% of men reporting first sex before age 16. On average, women married 1.8 years and men 6.1 years after their sexual debut. In women, age at sexual debut appears to have increased over time, in parallel with an increase in age at first marriage. Men were generally married later, to women around five to ten years younger than themselves. Marital dissolution and remarriage were common in both sexes. Reported numbers of sexual partners were compared with those recorded in a population survey in Britain. More men reported 10 or more lifetime partners, or three or more partners in the past year, in rural Mwanza (48% and 29%) than in Britain (24% and 6%). Women reported fewer partners, and results were broadly similar to British data. Casual sex during the past year was reported by 53% of the men and 15% of the women, but only 2% of men reported sexual contact with bar girls or commercial sex workers. Only 20% of men and 3% of women had ever used a condom. Interventions are needed to reduce the high levels of sexual partner change and casual sex, and low levels of condom use, recorded in this rural population. Targeting of interventions to traditional "core groups" may be of limited value in rural areas, and additional strategies are needed, focusing particularly on teenagers who are at high risk of HIV and other sexually transmitted diseases.

Thermal inactivation of bovine immunodeficiency virus

Cell-associated bovine immunodeficiency virus (BIV) and cell-free BIV were subjected to increasing temperatures, including pasteurization conditions. To determine the effect of heat treatment on BIV viability, reverse transcriptase activity and infectivity of the heat-treated virus were assessed. BIV was inactivated by heating to 47 degrees C for 30 min and by low- and high-temperature pasteurization conditions.

Transmission of HIV-1 in the breast-feeding process

Current laboratory techniques cannot distinguish the mode of vertical transmission (intrauterine, intrapartum, or postnatal) of human immunodeficiency virus type 1 (HIV-1) from mother to infant. The ability to transmit HIV-1 via breast feeding has been established in 24 case reports, primarily involving mothers who seroconvert after delivery. Whether breast-feeding adds a notable additional risk of HIV-1 infection to the risk from pregnancy is controversial. The importance of the duration and intensity of breast-feeding in modulating the outcome of HIV transmission via breast milk also remains unclear. Factors in breast milk may play important roles in an infant's susceptibility to infection with HIV and in the expression of the virus. Pasteurization and storage enhance the intrinsic, antiviral properties of human milk. Banked human milk is pasteurized to destroy the HIV-1 virus but retains properties that may be helpful to infants of HIV-1-positive mothers in developed countries where breast-feeding is not recommended. For infants in populations where the infant mortality rate is high, the risk of death associated with HIV infection acquired via breast milk is lower than the risk associated with not being breast-fed.

HIV-1 incidence and HIV-1 associated mortality in a cohort of urban factory workers in Tanzania

OBJECTIVE

To determine HIV-1 incidence and HIV-1 associated mortality in a prospective cohort study. To determine whether the cohort is suitable for studies aiming to determine the impact of interventions on HIV-1 incidence.

METHODS

The study population was a cohort of 1772 urban factory workers (1478 men and 294 women) in northwest Tanzania. The study took place from October 1991 to September 1993. Outcome measures were HIV-1 seroconversion and death.

RESULTS

HIV-1 incidence was 1.2 (95% CI 0.7-2.0) per 100 person-years (pyr). Crude annual mortality was 4.9 per 100 pyr in those with and 0.3 in those without HIV-1 infection, giving an age and sex adjusted mortality ratio of 12.9 (95% CI 5.4-30.7). Of all deaths, 62% were attributable to HIV-1 infection.

CONCLUSION

HIV-1 infection was a major public health problem, being the major cause of death in this adult population. At an HIV-1 incidence of 1.2 per 100 pyr, a large cohort size would be required to evaluate the impact of interventions on HIV-1 incidence.

Aids em crianças: considerações sobre a transmissão vertical

Trata-se de uma revisão sobre os aspectos epidemiológicos da síndrome de imunodeficiência adquirida em crianças e sobre a transmissão vertical do vírus da imunodeficiência humana (HIV). Discutem-se as diversas vias pelas quais o HIV pode transmitir-se de mãe para filho, abordando questões inerentes à fisiopatologia da infecção intra-útero, periparto e/ou pós-parto.