Isolation of AIDS virus from cell-free breast milk of three healthy virus carriers

When law and science part ways: the criminalization of breastfeeding by women living with HIV

Stigma and discrimination are a constant reality for the 37.7 million people living with human immunodeficiency virus (HIV) around the globe. Fear over vertical transmission has fuelled HIV criminalization: laws that target people living with HIV for acts deemed to be a transmission risk. Research has now shown that many of these behaviours, including breastfeeding, pose an extremely low risk of transmission when people have proper medical care, access to treatment and open relationships with medical professionals. Yet, we are witnessing a wave of criminal cases against women living with HIV for breastfeeding, an act which is actively promoted worldwide as the best infant feeding strategy. In this review, we will place the criminalization of breastfeeding within the context of current medical recommendations and cultural views of breastfeeding. We will highlight the criminal cases against women living with HIV for breastfeeding around the globe and the criteria for justifiable criminalization. Finally, we will provide recommendations for moving towards decriminalization, removing this barrier to HIV prevention, treatment and care.

Revisiting Koch's postulate to determine the plausibility of viral transmission by human milk

As breastfeeding is of utmost importance for child development and survival, identifying whether breast milk is a route of transmission for human viruses is critical. Based on the principle of Koch's postulate, we propose an analytical framework to determine the plausibility of viral transmission by breast milk. This framework is based on five criteria: viral infection in children receiving breast milk from infected mothers; the presence of virus, viral antigen, or viral genome in the breast milk of infected mothers; the evidence for the virus in breast milk being infectious; the attempts to rule out other transmission modalities; and the reproduction of viral transmission by oral inoculation in an animal model. We searched for evidence in published reports to determine whether the 5 criteria are fulfilled for 16 human viruses that are suspected to be transmissible by breast milk. We considered breast milk transmission is proven if all 5 criteria are fulfilled, as probable if 4 of the 5 criteria are met, as possible if 3 of the 5 criteria are fulfilled, and as unlikely if less than 3 criteria are met. Only five viruses have proven transmission through breast milk: human T-cell lymphotropic virus 1, human immunodeficiency virus, human cytomegalovirus, dengue virus, and Zika virus. The other 11 viruses fulfilled some but not all criteria and were categorized accordingly. Our framework analysis is useful for guiding public health recommendations and for identifying knowledge gaps amenable to original experiments.

Mistakes from the HIV pandemic should inform the COVID-19 response for maternal and newborn care

BACKGROUND

In an effort to prevent infants being infected with SARS-CoV-2, some governments, professional organisations, and health facilities are instituting policies that isolate newborns from their mothers and otherwise prevent or impede breastfeeding.

WEIGHING OF RISKS IS NECESSARY IN POLICY DEVELOPMENT

Such policies are risky as was shown in the early response to the HIV pandemic where efforts to prevent mother to child transmission by replacing breastfeeding with infant formula feeding ultimately resulted in more infant deaths. In the COVID-19 pandemic, the risk of maternal SARS-CoV-2 transmission needs to be weighed against the protection skin-to-skin contact, maternal proximity, and breastfeeding affords infants.

CONCLUSION

Policy makers and practitioners need to learn from the mistakes of the HIV pandemic and not undermine breastfeeding in the COVID-19 pandemic. It is clear that in order to maximise infant health and wellbeing, COVID-19 policies should support skin-to-skin contact, maternal proximity, and breastfeeding.

Transmission of CMV, HTLV-1, and HIV through breastmilk

Breastfeeding is a crucial child survival intervention. However, the potential for transmission of viral infections from mother to child presents the dilemma of how best to interpret the benefits and risks of breastfeeding in different settings. In this Review, we compare the transmission dynamics, risk factors, and outcomes of infection with three chronic viruses transmitted through breastmilk: cytomegalovirus, human T-cell lymphotropic virus type 1, and HIV. We provide an overview of intervention approaches and discuss scientific, policy, and programming gaps in the understanding of these major global infections.

HIV and SIV in Body Fluids: From Breast Milk to the Genitourinary Tract

HIV-1 is present in many secretions including oral, intestinal, genital, and breast milk. However, most people exposed to HIV-1 within these mucosal compartments do not become infected despite often frequent and repetitive exposure over prolonged periods of time. In this review, we discuss what is known about the levels of cell-free HIV RNA, cell-associated HIV DNA and cell-associated HIV RNA in external secretions. Levels of virus are usually lower than contemporaneously obtained blood, increased in settings of inflammation and infection, and decreased in response to antiretroviral therapy. Additionally, each mucosal compartment has unique innate and adaptive immune responses that affect the composition and presence of HIV-1 within each external secretion. We discuss the current state of knowledge about the types and amounts of virus present in the various excretions, touch on innate and adaptive immune responses as they affect viral levels, and highlight important areas for further study.

Why invest, and what it will take to improve breastfeeding practices?

Despite its established benefits, breastfeeding is no longer a norm in many communities. Multifactorial determinants of breastfeeding need supportive measures at many levels, from legal and policy directives to social attitudes and values, women's work and employment conditions, and health-care services to enable women to breastfeed. When relevant interventions are delivered adequately, breastfeeding practices are responsive and can improve rapidly. The best outcomes are achieved when interventions are implemented concurrently through several channels. The marketing of breastmilk substitutes negatively affects breastfeeding: global sales in 2014 of US$44·8 billion show the industry's large, competitive claim on infant feeding. Not breastfeeding is associated with lower intelligence and economic losses of about $302 billion annually or 0·49% of world gross national income. Breastfeeding provides short-term and long-term health and economic and environmental advantages to children, women, and society. To realise these gains, political support and financial investment are needed to protect, promote, and support breastfeeding.

The role of cell-associated virus in mother-to-child HIV transmission

Mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) continues to contribute to the global burden of disease despite great advances in antiretroviral (ARV) treatment and prophylaxis. In this review, we discuss the proposed mechanisms of MTCT, evidence for cell-free and cell-associated transmission in different routes of MTCT, and the impact of ARVs on virus levels and transmission. Many population-based studies support a role for cell-associated virus in transmission and in vitro studies also provide some support for this mode of transmission. However, animal model studies provide proof-of-principle that cell-free virus can establish infection in infants, and studies of ARVs in HIV-infected pregnant women show a strong correlation with reduction in cell-free virus levels and protection. ARV treatment in MTCT potentially provides opportunities to better define the infectious form of virus, but these studies will require better tools to measure the infectious cell reservoir.

Commonalities and differences in infant feeding attitudes and practices in the context of HIV in sub-Saharan Africa: a metasynthesis

Exclusive breastfeeding (EBF) has been identified as a key intervention to promote infant health and to reduce the vertical transmission of HIV. Despite this knowledge and increased resources to promote EBF, the practice in sub-Saharan Africa (SSA) remains low among HIV+ women. Although a number of qualitative studies have been conducted throughout SSA, the influences on and consequences of infant feeding choices of HIV+ mothers' findings have not been regarded systematically. Therefore, our objective was to identify overarching themes, commonalities, and differences in infant feeding choices among qualitative studies with HIV+ mothers in SSA. Sixteen qualitative studies of infant feeding practices in the context of HIV were identified. Noblit and Hare's seven-step metasynthesis methodology was used to analyze the experiences of HIV+ women and those who provide infant feeding services/counseling. Data were available from approximately 920 participants (i.e., 750 HIV+ mothers, 109 health-care providers, and 62 family members) across 13 SSA countries from 2000 to 2011. From these data, five themes emerged within which 3-4 overarching key metaphors were identified. The consistency of key metaphors across a variety of geographic, economic, and cultural settings suggest the importance of approaching infant feeding holistically, within the context of maternal knowledge, health-care support, family resources, and cultural expectations. EBF campaigns in SSA are more likely to successfully support optimal health for infants and a safe supportive environment for their mothers when the impact of infant feeding decisions are evaluated across these themes.

The oral mucosa immune environment and oral transmission of HIV/SIV

The global spread of human immunodeficiency virus (HIV) is dependent on the ability of this virus to efficiently cross from one host to the next by traversing a mucosal membrane. Unraveling how mucosal exposure of HIV results in systemic infection is critical for the development of effective therapeutic strategies. This review focuses on understanding the immune events associated with the oral route of transmission (via breastfeeding or sexual oral intercourse), which occurs across the oral and/or gastrointestinal mucosa. Studies in both humans and simian immunodeficiency virus (SIV) monkey models have identified viral changes and immune events associated with oral HIV/SIV exposure. This review covers our current knowledge of HIV oral transmission in both infants and adults, the use of SIV models in understanding early immune events, oral immune factors that modulate HIV/SIV susceptibility (including mucosal inflammation), and interventions that may impact oral HIV transmission rates. Understanding the factors that influence oral HIV transmission will provide the foundation for developing immune therapeutic and vaccine strategies that can protect both infants and adults from oral HIV transmission.

The role of co-infections in mother-to-child transmission of HIV

In HIV-infected women, co-infections that target the placenta, fetal membranes, genital tract, and breast tissue, as well as systemic maternal and infant infections, have been shown to increase the risk for mother-to-child transmission of HIV (MTCT). Active co-infection stimulates the release of cytokines and inflammatory agents that enhance HIV replication locally or systemically and increase tissue permeability, which weakens natural defenses to MTCT. Many maternal or infant co-infections can affect MTCT of HIV, and particular ones, such as genital tract infection with herpes simplex virus, or systemic infections such as hepatitis B, can have substantial epidemiologic impact on MTCT. Screening and treatment for co-infections that can make infants susceptible to MTCT in utero, peripartum, or postpartum can help reduce the incidence of HIV infection among infants and improve the health of mothers and infants worldwide.

Exclusive breastfeeding reduces risk of mortality in infants up to 6 mo of age born to HIV-positive Tanzanian women

BACKGROUND

Despite the benefits of exclusive breastfeeding (EBF), exposure to HIV from breast milk has relegated EBF to an option only when formula feeding is not affordable, feasible, safe, and sustainable. Mixed feeding remains the norm in sub-Saharan Africa.

OBJECTIVE

We evaluated whether the duration of EBF was associated with mortality and HIV infection in children followed to ≤5 y of age.

METHODS

A total of 690 mother-infant pairs from the Trial of Vitamins with information on infant feeding, HIV status, and at least one visit in the first year were included in the analysis. The duration of EBF was defined in months as a time-varying covariate at each follow-up visit. Associations of the duration of EBF with mortality, HIV infection, and HIV infection or death were estimated by using Cox proportional hazards models and Kaplan-Meier survival curves.

RESULTS

A 1-mo increase in EBF was associated with a 49% reduction in early infant mortality in the first 6 mo of life (RR: 0.51; 95% CI: 0.28, 0.93) and a nonsignificant 15% reduction in risk of HIV infection or death (RR: 0.85; 95% CI: 0.71, 1.01; P = 0.07) over the first 5 y of life. EBF was not associated with HIV infection (RR: 0.93; 95% CI: 0.76, 1.15).

CONCLUSION

Longer EBF by HIV-positive mothers was associated with reduced mortality in the first 6 mo of life without increased HIV infection, which makes EBF the best option for women who cannot sustain exclusive formula feeding. This trial was registered at clinicaltrials.gov as NCT00197743.

The urban poor: an appropriate population for breastfeeding promotion programs

Breastfeeding has won universal endorsement as a major contributor to child survival. The proliferation of breastfeeding promotion programs demonstrates the importance health professionals and funding agencies place on improving the incidence and duration of breastfeeding. An effective, cost-efficient breastfeeding promotion program should be directed at those who will receive the greatest health benefit from such an intervention, i.e., the group who 1) would experience the greatest threat to health by decreasing its breastfeeding practice, and 2) is at greatest risk of changing its breastfeeding habits. Since it is the urban poor primarily who satisfy both of these criteria breastfeeding promotion strategies should focus on them.

Breastfeeding and HIV: experiences from a decade of prevention of postnatal HIV transmission in sub-Saharan Africa

Infant feeding by HIV-infected mothers has been a major global public health dilemma and a highly controversial matter. The controversy is reflected in the different sets of WHO infant feeding guidelines that have been issued over the last two decades. This thematic series, 'Infant feeding and HIV: lessons learnt and ways ahead' highlights the multiple challenges that HIV-infected women, infant feeding counsellors and health systems have encountered trying to translate and implement the shifting infant feeding recommendations in different local contexts in sub-Saharan Africa. As a background for the papers making up the series, this editorial reviews the changes in the guidelines in view of the roll out of prevention of mother to child transmission (PMTCT) programmes in sub-Saharan Africa between 2001 and 2010.

Determinants of infant feeding choices by Zambian mothers: a mixed quantitative and qualitative study

Choosing an infant feeding mode is complex for human immunodeficiency virus (HIV)-infected African women. We documented infant feeding choices by 811 mothers of infants aged less than 18 months enrolled in the Chilenje Infant Growth, Nutrition and Infection Study of fortified complementary or replacement foods. We also conducted 20 interviews and 4 focus group discussions among women and nurses to explore the issues in depth. Practices of most HIV-infected women did not closely follow national or international guidelines: 26% never initiated breastfeeding, and 55% were not breastfeeding by 6 months post partum. Women of lower socio-economic status and those not meeting criteria for safe replacement feeding were more likely to initiate breastfeeding, to continue longer and to stop at 6 months when provided with free food within the trial. Most HIV-negative women and women of unknown HIV status continued breastfeeding into the infant's second year, indicating limited 'spillover' of infant feeding messages designed for HIV-infected women into the uninfected population. Qualitative work indicated that the main factors affecting HIV-infected women's infant feeding decisions were the cost of formula, the advice of health workers, influence of relatives, stigma and difficulties with using an exclusive feeding mode. Rapidly changing international recommendations confused both mothers and nurses. Many HIV-infected women chose replacement feeding without meeting criteria to do this safely. Women were influenced by health workers but, for several reasons, found it difficult to follow their advice. The recently revised international HIV and infant feeding recommendations may make the counselling process simpler for health workers and makes following their advice easier for HIV-infected women.

German-Austrian recommendations for HIV1-therapy in pregnancy and in HIV1-exposed newborn, update 2008

In Germany during the last years about 200-250 HIV1-infected pregnant women delivered a baby each year, a number that is currently increasing. To determine the HIV-status early in pregnancy voluntary HIV-testing of all pregnant women is recommended in Germany and Austria as part of prenatal care. In those cases, where HIV1-infection was known during pregnancy, since 1995 the rate of vertical transmission of HIV1 was reduced to 1-2%. - This low transmission rate has been achieved by the combination of anti-retroviral therapy of pregnant women, caesarean section scheduled before onset of labour, anti-retroviral post exposition prophylaxis in the newborn and refraining from breast-feeding by the HIV1-infected mother. To keep pace with new results in research, approval of new anti-retroviral drugs and changes in the general treatment recommendations for HIV1-infected adults, in 1998, 2001, 2003 and 2005 an interdisciplinary consensus meeting was held. Gynaecologists, infectious disease specialists, paediatricians, pharmacologists, virologists and members of the German AIDS Hilfe (NGO) were participating in this conference to update the prevention strategies. A fifth update became necessary in 2008. The updating process was started in January 2008 and was terminated in September 2008. The guidelines provide new recommendations on the indication and the starting point for HIV-therapy in pregnancies without complications, drugs and drug combinations to be used preferably in these pregnancies and updated information on adverse effects of anti-retroviral drugs. Also the procedures for different scenarios and risk constellations in pregnancy have been specified again. - With these current guidelines in Germany and Austria the low rate of vertical HIV1-transmission should be further maintained.

Inhibition of human immunodeficiency virus type 1 activity by purified human breast milk mucin (MUC1) in an inhibition assay

It has been reported that breast-feeding is responsible for approximately 40% of the HIV transmissions from HIV-positive mothers to children. Human breast milk, however, is known to contain numerous biologically active components which protect breast-fed infants against bacteria, viruses, and toxins. The purpose of this study was to purify and characterize breast milk mucin and to determine its anti-HIV-1 activity in an HIV inhibition assay. Sepharose CL-4B column chromatography and caesium chloride isopycnic density gradient purification were used to isolate and purify the mucin. Following Western blotting and amino acid analysis, an HIV-1 inhibition assay was carried out to determine the anti-HIV-1 activity of crude breast milk and purified milk mucin (MUC1) by incubating them with HIV-1 prior to infection of the human T lymphoblastoid cell line (CEM SS cells). SDS-PAGE analysis of the mucin, together with its amino acid composition and Western blotting, suggested that this purified mucin from human breast milk was MUC1. The HIV inhibition assay revealed that while the purified milk mucin (MUC1) inhibited the HIV-1 activity by approximately 97%, there was no inhibition of the HIV-1 activity by crude breast milk. Although the reason for this is not clear, it is likely that because the MUC1 in crude milk is enclosed by fat globules, there may not be any physical contact between the mucin and the virus in the crude breast milk. Thus, there is a need to free the mucin from the fat globules for it to be effective against the virus.

Infant feeding and HIV in Sub-Saharan Africa: what lies beneath the dilemma?

The debate over how to best guide HIV-infected mothers in resource-poor settings on infant feeding is more than two decades old. Globally, breastfeeding is responsible for approximately 300,000 HIV infections per year, while at the same time, UNICEF estimates that not breastfeeding (formula feeding with contaminated water) is responsible for 1.5 million child deaths per year. The largest burden of these infections and deaths occur in Sub-Saharan Africa. Using this region as an example of the burden faced more generally in other resource-poor settings, we contrast the evolution of the clinical standard of care for infant feeding with HIV-infected mothers in high-income countries to the current international clinical guidelines for HIV-infected mothers and infant feeding in resource-poor settings. While the international guidelines of exclusive breastfeeding for a 6-month period seem to offer the least-worst strategy for reducing mother-to-child transmission of HIV during infancy while conferring some immunity through breastfeeding post-6 months, we argue that the impact of the policy on mothers and healthcare workers on the ground is not well understood. The harm reduction approach on the level of health policy translates into a complicated, painful moral dilemma for HIV-positive mothers and those offering them guidance on infant feeding. We argue that the underlying socio-economic disparities that continue to fuel the need for a harm reduction policy on infant feeding and the harm to women and children justify: (1) that higher priority be given to solving the infant feeding dilemma with improved data on safe feeding alternatives, and (2) support of innovative, community-driven solutions that address the particular economic and cultural challenges that continue to result in HIV-transmission to children within these communities.

HIV-1 variants from a perinatal transmission pair demonstrate similar genetic and replicative properties in tonsillar tissues and peripheral blood mononuclear cells

Human immunodeficiency virus type 1 (HIV-1) can be acquired through oropharyngeal tissues in breastfeeding infants. Efforts to better understand the determinants of breast milk transmission are hampered by the lack of a relevant oral human mucosa model and well-defined breast milk-derived viruses. This study used human ex vivo palatine tonsil tissues and peripheral blood mononuclear cells (PBMCs) to characterize the genetic, biological, and replicative properties of HIV-1 variants obtained from a perinatal transmission pair. Unique viral populations from maternal breast milk and infant blood were identified by gp120 V1-V2- and V3-specific heteroduplex tracking assays (HTAs). Full-length infectious recombinant viruses, containing a common HIV-1 NL4-3 genetic background, were generated with V1-V3 gp120 fragments from maternal and infant isolates representing the major viral populations identified in the HTAs. The resulting recombinant viruses used the CCR5 coreceptor, were nonsyncytium forming, and demonstrated replication properties similar to those of parental and control viruses in PBMCs and tonsillar explants. These findings indicate that viruses from breast milk cells and infant blood can infect PBMCs and tonsil tissues. The maternal and infant HIV-1 viruses detailed here will provide useful tools for defining the viral and host factors that contribute to HIV breastfeeding transmission.

Evidence of proviral clearance following postpartum transmission of an ovine lentivirus

Lentiviral transmission by transfer of infected colostrum and/or milk is considered to be highly efficient. In this study, postpartum transmission of ovine progressive pneumonia virus (OPPV) from 10 naturally infected ewes to their 23 lambs was followed from the perinatal period throughout a four-year period. The lambs were allowed to suckle from their dam from birth through 32 weeks of age. Virus was tracked by virus isolation, quantitative PCR (qPCR), and anti-OPPV antibody responses as measured by cELISA. Cell-associated OPPV was isolated from colostrum/milk cells in 7 out of 10 ewes and provirus envelope (env) loads ranged 8 to 10(5) copies/mug DNA in colostrum/milk cells from the 10 ewes using qPCR. Provirus env loads were also detected in the peripheral circulation of 21 lambs at 8 weeks and two lambs at 22 weeks. The qPCR product at 8 weeks was confirmed as the transmembrane (tm) gene of OPPV by cloning and sequencing. Both cELISA titers ranging from 325 to 3125 and cross-neutralizing antibody titers ranging from 6 to 162 to seven different OPPV strains were found in the colostrum of the 10 ewes. Furthermore, cELISA titers in serum from lambs remained detectable through 32 weeks following the clearance of provirus at 24 weeks. After 32 weeks, both provirus and anti-OPPV antibody responses have subsequently remained undetectable through 4 years of age. These data suggest the clearance of cell-associated lentiviruses from lamb circulation after passive transfer of antibody via colostrum.

Benefits and risks of breastfeeding

In the absence of significant, unpreventable risks, breastfeeding should be the norm for the nourishment of human infants and should, therefore, be encouraged for populations in all countries. Continued efforts of international and national agencies and healthcare professionals to aid and abet breastfeeding, reduce the risks that occur in some women during breastfeeding, provide the safest substitutes for human milk when that is necessary, and encourage further research into the posed questions should considerably improve the health of many children.

Alternative modified infant-feeding practices to prevent postnatal transmission of human immunodeficiency virus type 1 through breast milk: past, present, and future

Preventing mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) through breastfeeding is important to reduce the number of infected children. Research on making breastfeeding safer is a high priority. The authors reviewed the attempts to develop alternative methods, other than antiretroviral (ARV) therapy of mothers and/or babies, to decontaminate breast milk of infectious HIV-1 (free and associated with lymphocytes). They also review how these methods affect milk constituents, as well as their current and prospective status. A PubMed search for English publications on methods to prevent MTCT through breast milk was completed. Methods that have been tested, other than systemicuse or ARV or immunoprophylaxis, to reduce or prevent MTCT of HIV-1 through breast milk were broadly classified into 5 groups: (1) modified feeding practices, (2) heat treatment of milk, (3) lipolysis, (4) antimicrobial treatment of the breastfeeding mother, and (5) microbicidal treatment of infected milk. Their advantages and disadvantages are discussed, as well as future directions in the prevention of MTCT through breastfeeding.

HIV and pregnancy in Australia

It is estimated there are over 19 million women worldwide living with HIV infection. In Australia the total number of notified cases of HIV in women has been gradually increasing (the estimated number of women newly diagnosed with HIV infection was 78 in 2000 and 94 in 2001). Management of women in pregnancy and strategies to reduce perinatal transmission is critical, but differ significantly according to resource availability. The current review examines the best available scientific evidence and current guidelines for optimal management of HIV-infected women contemplating pregnancy in Australia.

Oro-facial manifestations in paediatric HIV: a comparative study of institutionalized and hospital outpatients

The aim of the study was to compare dental caries status and the number and type of oral mucosal lesions in HIV positive children from a hospital outpatient department and an institutionalized setting. Oral examinations were performed using presumptive diagnostic criteria. The Fisher's Exact and the Mann-Whitney tests were used for statistical comparison of the two study groups. A total of 169 children were examined of whom 42% were institutionalized and 58% hospital outpatients. One institutionalized child presented with Noma. Twenty-one percent of the institutionalized population presented with molluscum contagiosum, while none of the hospital outpatients presented with this condition. Significantly more intraoral mucosal lesions were observed in the hospital compared with the institutionalized group. The most frequently encountered oral lesion was candidiasis. Pseudomembranous candidiasis was the most common type. Twice as many intraoral ulcers were recorded in the institutionalized group. Thirty-nine percent of the hospitalized patients had multiple lesions compared with 28% in the institutionalized group. Almost three quarters of both populations were caries-free. The mean DMFT was considerably higher in the hospital population. For both the permanent and primary teeth, the decayed component (D/d) made up the major part of the DMFT/dmft, followed by the missing (M/m) component. No fillings were recorded in either the primary or permanent teeth for both groups. Oral lesions are common in HIV populations and were seen in both the hospital and institutionalized groups, at high prevalence levels (63 and 45%). HIV infected children should be considered high risk for caries because of the use of chronic medications, and to receive appropriate care in terms of both treatment and services.

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.

The low viral production in trophoblastic cells is due to a high endocytic internalization of the human immunodeficiency virus type 1 and can be overcome by the pro-inflammatory cytokines tumor necrosis factor-alpha and interleukin-1

Maternal-infant transmission of human immunodeficiency virus type-1 (HIV-1) is the primary cause of this retrovirus infection in neonates. Trophoblasts have been proposed to play a critical role in modulating virus spread to the fetus. This paper addresses the mechanism of HIV-1 biology in trophoblastic cells. The trophoblastic cell lines BeWo, JAR, and JEG-3 were infected with reporter HIV-1 particles pseudotyped with envelope glycoproteins from the vesicular stomatitis virus or various strains of HIV-1. We demonstrate that despite a high internalization process of HIV-1 and no block in viral production, HIV-1 established a limited infection of trophoblasts with the production of very few progeny viruses. The factor responsible for this restriction to virus replication in such a cellular microenvironment is that the intracellular p24 is concentrated predominantly in endosomal vesicles following HIV-1 entry. HIV-1 transcription and virus production of infectious particles were both augmented upon treatment of trophoblasts with tumor necrosis factor-alpha and interleukin-1. However, the amount of progeny virions released by trophoblasts infected with native HIV-1 virions was so low even in the presence of pro-inflammatory cytokines that a co-culture step with indicator cells was necessary to detect virus production. Collectively these data illustrate for the first time that the natural low permissiveness of trophoblasts to productive HIV-1 infection is because of a restriction in the mode of entry, and such a limitation can be overcome with physiologic doses of tumor necrosis factor-alpha and interleukin-1, which are both expressed by the placenta, in conjunction with cell-cell contact. Considering that there is a linear correlation between viral load and HIV-1 vertical transmission, the environment may thus contribute to the propagation of HIV-1 across the placenta.

Vertical transmission of human immunodeficiency virus

Sensitive detection methods, such as DNA PCR and RNA PCR suggest that vertical transmission of human immunodeficiency virus (HIV) occurs at three major time periods; in utero, around the time of birth, and postpartum as a result of breastfeeding (Fig. 1). Detection of proviral DNA in infant's blood at birth suggests that transmission occurred prior to delivery. A working definition for time of infection is that HIV detection by DNA PCR in the first 48 h of life indicates in utero transmission, while peripartum transmission is considered if DNA PCR is negative the first 48 h, but then it is positive 7 or more days later [1]. Generally, in the breastfeeding population, breast milk transmission is thought to occur if virus is not detected by PCR at 3-5 months of life but is detected thereafter within the breastfeeding period [2]. Using these definitions and guidelines, studies has suggested that in developed countries the majority, or two thirds of vertical transmission occur peripartum, and one-third in utero [3-6]. The low rate of breastfeeding transmission is due to the practice of advising known HIV-positive mothers not to feed breast milk. However, since the implementation of antiretroviral treatment in prophylaxis of HIV-positive mothers, some studies have suggested that in utero infection accounts for a larger percentage of vertical transmissions [7]. In developing countries, although the majority of infections occurs also peripartum, a significant percentage, 10-17%, is thought to be due to breastfeeding [2, 8, 9].

Micronutrients and vertical transmission of HIV-1

ABSTRACT Vertical transmission of HIV from mother to infant can occur during pregnancy, at the time of delivery, or post-natally through breast-feeding and is a major factor in the continuing spread of HIV infection. Inadequate nutritional status may increase the risk of vertical HIV transmission by influencing mater-nal and child factors for transmission. The potential effects on these factors include impaired systemic immune function in pregnant women, fetuses, and children; an increased rate of clinical, immunologic, and virologic disease progression; impaired epithelial integrity of the placenta and genital tract; increased viral shedding in breast milk from inflammation of breast tissue; increased risk of low birth weight and preterm birth; and impaired gastrointestinal immune function and integrity in fetuses and children. Micronutrient deficiencies are prevalent in many HIV-infected populations, and numerous studies have reported that these deficiencies impair immune responses, weaken epithelial integrity, and are associated with accelerated HIV disease progression. Although low serum vitamin A concentrations were shown to be associated with an increased risk of vertical HIV transmission in prospective cohort studies, randomized, placebo-controlled trials have reported that vitamin A and other vitamin supplements do not appear to have an effect on HIV transmission during pregnancy or the intrapartum period. However, the ability of prenatal and postpartum micronutrient supplements to reduce transmission during the breast-feeding period is still unknown.

[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.

Mastitis and transmission of human immunodeficiency virus through breast milk

Mastitis, an inflammation in the breast, has recently been linked with higher human immunodeficiency virus (HIV) load in breast milk and higher risk of mother-to-child transmission of HIV. Among 334 HIV-infected women in Malawi who were breastfeeding, the prevalence of mastitis, as indicated by elevated breast milk sodium, was 16.4% at six weeks and 2.8% at six months postpartum. Mastitis is associated with significantly higher concentrations of immunological and inflammatory mediators in breast milk, including lactoferrin, lysozyme, secretory leukocyte protease inhibitor, interleukin-8, and RANTES. Mastitis is potentially preventable by improving micronutrient status of breastfeeding women and can be treated with antibiotics and clinical management. These studies in Malawi suggest that mastitis may contribute to transmission of HIV through breast milk.

Cell-free virus in breast milk of HIV-1-seropositive women

To examine the prevalence, quantification, and factors that influence HIV in the cell-free compartment of breast milk, we performed reverse transcription polymerase chain reaction (RT-PCR) on samples obtained from HIV-1-infected study subjects. Virus was detected in 86 of 136 samples (63.2%) from 79 study subjects. HIV RNA quantity ranged from undetectable to 227,586 copies/ml. Prevalence and mean viral load were not affected by postnatal ages or maternal vitamin A supplementation. Among study subjects with multiple samples, breast milk viral load did not change at different postnatal ages. Breast milk viral load correlated positively with plasma viral load (r = 0.47; p =.005) and negatively with maternal CD4 count at entry to the study (r = -0.26; p =.02). Mothers of HIV-infected children had a higher proportion of detectable HIV RNA in their breast milk than mothers of uninfected children (p =.03) and higher mean log10 HIV RNA quantities (p =.04). In a multivariate logistic regression model, log10 HIV RNA quantity in breast milk was significantly associated with the risk of mother-child transmission (odds ratio [OR], 2.82; 95% confidence interval [CI], 1.22-6.51). Thus, prevention and treatment of opportunistic infections and of mastitis and early weaning may be important elements of a public health policy that is relevant to women in developing countries with HIV infection. Where available, antiretrovirals may also have an impact on opportunistic infections and mastitis.

Cytokine profiles in parotid saliva from HIV-1-infected individuals: changes associated with opportunistic infections in the oral cavity

The purpose of this study was to quantitate levels of cytokines in parotid saliva of subjects infected with human immunodeficiency virus-1 (HIV-1) and to determine if the cytokine profiles differ in subjects with an oral opportunistic infection, i.e., candidiasis or oral hairy leukoplakia. Parotid saliva samples were obtained from HIV-infected individuals with or without candidiasis or oral hairy leukoplakia and from healthy controls and were assessed by ELISA for levels of interleukin (IL)-1, IL-2, IL-4, IL-5, IL-10, transforming growth factor-beta, tumor necrosis factor-alpha and interferon (IFN)-gamma. Saliva from HIV-infected subjects with oral candidiasis had significantly higher levels of IFN-gamma than that seen in HIV-infected individuals with no oral disease and significantly higher levels of IL-2, IL-5 and IFN-gamma than saliva of healthy controls. No significant difference was seen in cytokine levels in saliva from HIV-infected subjects with no oral infections and healthy controls. The HIV-infected subjects with oral hairy leukoplakia displayed significantly higher levels of both IL-1 alpha and IFN-gamma compared with the HIV and no oral disease group and a higher level of IFN-gamma than seen in saliva from the healthy control group. In comparing cytokine levels from both HIV and oral disease groups, significant differences were detected in levels of IL-5 and IL-10. These results indicate that the profile of salivary cytokines is altered as a result of the oral opportunistic infection candidiasis or oral hairy leukoplakia and also by concurrent HIV infection.

A human milk factor susceptible to cathepsin D inhibitors enhances human immunodeficiency virus type 1 infectivity and allows virus entry into a mammary epithelial cell line

Human immunodeficiency virus type 1 (HIV-1) growth in lymphocyte cultures was increased when the virus inoculum was incubated in breast milk. The enhancing effect of milk was abolished by anti-cathepsin D antibody or by pepstatin A, a cathepsin D inhibitor. The cathepsin D-producing CD4-negative MCF7 mammary cells supported the growth of some HIV-1 isolates. An MCF7 line chronically producing HIV-1 IIIb was obtained. Cathepsin D may induce conformational modification of viral gp120, allowing direct interaction with a coreceptor. We demonstrated the presence of CXCR4 mRNA in MCF7 cells.