Search Results (91)

Chronic hepatitis B virus (HBV) infection is a major health problem that leads to approximately one million deaths every year worldwide. Mother-to-child transmission (MTCT) is the major cause of chronic HBV infection. HBV e antigen (HBeAg) is a secretory viral protein and modulates the immunological landscape of the newborn to promote HBV persistence. HBeAg actively reprograms innate and adaptive immunity. Mechanistically, HBeAg regulates macrophage polarization, suppresses dendritic cell and natural killer (NK) cell activities, impairs T cell and B cell functions, and promotes the expansion of myeloid-derived suppressor cells (MDSCs). These multifaceted effects contribute to immune tolerance and persistent HBV infection in the offspring of carrier mothers. Clinically, HBeAg status is a critical determinant for MTCT risk stratification and intervention, particularly in resource-limited settings. Despite advances in neonatal immunoprophylaxis and maternal antiviral therapy, residual transmission of HBV persists. Emerging approaches targeting HBeAg directly or restoring antiviral immunity offer promising avenues for breaking immune tolerance and achieving HBV elimination. This review summarizes current understanding of HBeAg-mediated immune modulation and highlights strategies that are being used to disrupt MTCT and treat HBV patients. Full article

In this study we aimed to investigate the levels of selected heavy metals and trace elements (Hg, Pb, Cd, As, Mn, Se, and Cu) in three different biomatrices—maternal urine (Mu), neonatal urine (Nu), and cord blood—of preterm newborns born at less than 35 weeks’ gestation who were staying in the NICU and their mothers, and the relationships of these elements with maternal and neonatal characteristics. Cord Pb, As, and Hg were significantly lower than in Mu, whereas Se and Cu were higher (p < 0.001). All elements were excreted more in Mu than in Nu (p < 0.001). Nu levels of Cd, Mn, Se, and Cu were lower, while As and Hg were higher than in cord blood. Nu metal excretion increased significantly over time (p < 0.001). Positive correlations were found between MuCu and NuCu (r_s = 0.35) and between maternal Se and maternal age (r_s = 0.41). NuHg, MuMn, and cord Mn showed negative correlations with penile length, and NuHg was also negatively correlated with anogenital distance. The first and second NuPb levels were positively correlated with birth weight percentile. The findings suggest transplacental transmission and ongoing exposure to heavy metals and trace elements in preterm infants, highlighting the importance of prenatal environmental exposure awareness for healthcare providers. Full article

Introduction: Eliminating mother-to-child transmission (EMTCT) of HIV is a global health priority to ensure that no child is born with HIV. When EMTCT services are underutilized, mothers and babies face greater risks, including the vertical transmission of HIV and higher rates of maternal and neonatal mortality. Despite ongoing efforts, many women worldwide still struggle to access and use these vital services. Objective: This study sought to explore barriers and facilitators to the elimination of mother-to-child transmission services among pregnant and breastfeeding women (PBFW) in Gauteng province, South Africa. Methods: A qualitative, explorative, and descriptive research design was used. Convenience and purposive sampling were used to select participants. The study population consisted of PBFW aged 18 years or above who were utilizing EMTCT services. Data was collected through in-depth face-to-face individual interviews with participants. A semi-structured interview guide was used to collect data until data saturation was reached after interviewing 25 participants. Data were analyzed using thematic analysis (Tesch’s open coding method). Trustworthiness and ethical principles were ensured. Results: Four main themes emerged from the data analyzed, namely, barriers associated with EMTCT service utilization, facility-based strategies to improve EMTCT service uptake, community support for enhancing EMTCT engagement, and the role of partner support in service utilization, each with linked sub-themes. This study found that health education about EMTCT, along with community awareness and involvement, encourages the target group to utilize these services. Conclusions: Increasing women’s use of EMTCT services is an important step toward eliminating MTCT and increasing the health and well-being of mothers and their children. Addressing numerous barriers to receiving these services, as well as implementing targeted measures, can help ensure that all women gain access to the care and support that they require to safeguard their families from HIV. Full article

Postnatal cytomegalovirus (pCMV) infection is typically asymptomatic in term infants but poses significant risks to very preterm and very low birth weight (VLBW) infants. The primary mode of transmission of pCMV is breast milk from seropositive mothers. Here, we present the case of a 29-week preterm female who contracted pCMV and began to manifest symptoms at day of life (DOL) 50. She developed respiratory compromise, massive ascites, and was extremely ill. The patient was managed with ganciclovir (GCV), intravenous immunoglobulins (IVIG), and percutaneous drainage of the ascites. She gradually improved and was discharged after a 5-month neonatal intensive care unit (NICU) stay. After presenting the case, we review the clinical manifestations of pCMV, and particularly its less well-recognized gastrointestinal manifestations, including ascites. We then outline guidelines for treatment and prevention. Clinicians should consider pCMV in VLBW and extremely premature infants presenting with thrombocytopenia, colitis, or ascites, especially in the second and third months of life. Full article

Human T-cell lymphotropic virus (HTLV), a retrovirus associated with severe conditions such as leukemia/lymphoma and myelopathy, exhibits variable global prevalence, with higher rates observed in regions such as northeastern Brazil and sub-Saharan Africa. While intrauterine transmission can occur via viral expression in placental tissue and contact with umbilical cord blood, the predominant route is vertical transmission through breastfeeding. Diagnostic testing, particularly serological screening with ELISA and confirmatory methods such as Western blot and PCR, is essential for early detection during pregnancy. The implementation of prenatal screening programs, as seen in Japan and Brazil, has proven effective in reducing vertical transmission by guiding interventions such as breastfeeding cessation in infected mothers. Beyond clinical implications, the psychosocial impact on affected pregnant women highlights the need for an interdisciplinary approach. Although the association between HTLV infection and adverse obstetric outcomes remains controversial, studies suggest increased risks of preterm birth, low birth weight, and other neonatal complications. Given the importance of early diagnosis and prevention, universal prenatal screening protocols represent a critical strategy to reduce viral transmission and its long-term consequences. Full article

Pregnancy introduces significant physiological changes that alter the pharmacokinetics (PK) of antiretroviral therapy (ART), impacting its safety and efficacy in HIV-positive women. Optimizing ART during pregnancy is critical to maintaining maternal virological suppression and preventing mother-to-child transmission (MTCT) of HIV. This review evaluates the impact of pregnancy-induced PK changes on ART and proposes strategies for tailored regimens to improve outcomes. A comprehensive review of published literature was conducted, focusing on PK adaptations during pregnancy and their implications for different ART classes, including protease inhibitors (PIs), integrase strand transfer inhibitors (INSTIs), and nucleoside reverse transcriptase inhibitors (NRTIs). Key studies were analyzed to assess drug exposure, efficacy, and safety. Pregnancy significantly alters the PK of antiretrovirals, with increased hepatic metabolism, renal clearance, and changes in plasma protein binding leading to reduced drug exposure. For example, drugs like lopinavir and atazanavir require dose adjustments, while dolutegravir maintains efficacy despite reduced plasma levels. Integrase inhibitors demonstrate favorable virological suppression, although cobicistat-boosted regimens show subtherapeutic levels. Tailored approaches, such as therapeutic drug monitoring (TDM), optimize ART efficacy while minimizing toxicity. Pregnancy-specific PK changes necessitate evidence-based ART adjustments to ensure virological suppression and reduce MTCT risk. Incorporating TDM, leveraging pharmacogenomic insights, and prioritizing maternal and neonatal safety are critical for personalized ART management. Further research into long-acting formulations and global guideline harmonization is needed to address disparities in care and improve outcomes for HIV-positive pregnant women. Full article

Background/Objectives: The World Health Organization (WHO) declared a global pandemic of COVID-19 caused by SARS-CoV-2 in March 2020. May 2023 was the month that ended the global pandemic. Pregnant females with COVID-19 are less likely to be symptomatic than non-pregnant patients, with nearly three-quarters being without symptoms. According to previous studies, even if somebody develops symptoms, they are usually mild, most commonly coughing (41%), fever (40%), and dyspnea (21%). Our study aims to search the literature systematically, especially case series and case reports published in Europe, and to summarize results about the kind of COVID-19 therapy in pregnant women and about outcomes in mothers and newborns. Methods: Our systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) with CRD42024566838. We searched PubMed/MEDLINE, Google Scholar, Web of Science, Scopus, and Serbian Citation Index (SCIndeks). In this study, case reports or case series with open, complete text that included full clinical records of the individuals identified with infection in pregnancy, thought to be caused by COVID-19, were used. Case series or case reports were eliminated if they (1) did not contain a full clinical report for every patient, or (2) included an individual who suffered from another viral infection other than COVID-19, so the clinical course and the outcome could not be precisely defined. We evaluated reporting bias and attrition bias. Results: Our study included 32 published studies (eight case series and 24 case reports) that included 56 individual cases. The oldest patient was 50 years old, and the youngest was 19 years old. The most common symptom initially was dry cough (n = 23; 41%), followed by fever (n = 21; 37%) and dyspnea (n = 10; 17%). In three patients, a lower level of thrombocytes was reported, with the lowest level of 86 × 10⁹. The most frequently used drugs in pregnant women with COVID-19 infection were azithromycin, lopinavir/ritonavir, hydroxychloroquine, as well as corticosteroids. Twenty-two patients were on mechanical ventilation. After all this reported therapy, ten women died, as well as seven newborns. Conclusions: From our results, we can conclude that mechanical ventilation correlates with cesarean section performed more frequently, as well as with a higher mortality rate of neonates. There are no significant data related to transplacental transmission of the virus. Generally, mortality in our group of patients (mothers) was 17%, which is similar to the general population death from COVID-19 infection. Full article

The pathogenesis of obesity is complex and incompletely understood, with an underlying interplay between our genetic architecture and obesogenic environment. The public understanding of the development of obesity is shrouded in myths with widespread societal misconceptions. Body Mass Index (BMI) is a highly heritable trait. However, despite reports from recent genome-wide association studies, only a small proportion of the overall heritability of BMI is known to be lurking within the human genome. Other non-genetic heritable traits may contribute to BMI. The gut microbiome is an excellent candidate, implicating complex interlinks with hypothalamic control of appetite and metabolism via entero-endocrine, autonomic, and neuro-humeral pathways. The neonatal gut microbiome derived from the mother via transgenerational transmission (vaginal delivery and breastfeeding) tends to have a permanence within the gut. Conversely, non-maternally derived gut microbiota manifest mutability that responds to changes in lifestyle and diet. We should all strive to optimize our lifestyles and ensure a diet that is replete with varied and unprocessed plant-based foods to establish and nurture a healthy gut microbiome. Women of reproductive age should optimize their gut microbiome, particularly pre-conception, ante- and postnatally to enable the establishment of a healthy neonatal gut microbiome in their offspring. Finally, we should redouble our efforts to educate the populace on the pathogenesis of obesity, and the role of heritable (but modifiable) factors such as the gut microbiome. Such renewed understanding and insights would help to promote the widespread adoption of healthy lifestyles and diets, and facilitate a transition from our current dispassionate and stigmatized societal approach towards people living with obesity towards one that is epitomized by understanding, support, and compassion. Full article

Objectives: The hospital organizational model can have an impact on people’s health. A critical lesson can be drawn from the pandemic. The possible negative sequelae of the practice of separation of maternal–infant dyads adopted during an infant’s first SARS-CoV-2 pandemic infection on infants have not been considered. Our purpose was to investigate the short- and long-term effects on neonates born to SARS-CoV-2 infected mothers of two different mother–infant dyad management strategies after birth (Separation vs. Rooming-In). Methods: This prospective cohort study enrolled 60 pregnant women who tested positive for SARS-CoV-2 infection and their newborns. We identified two cohorts of study based on mother–infant dyad management after delivery: Cohort A (Separation) and Cohort B (Rooming-In). Inclusion criteria were neonates born from mothers infected with SARS-CoV-2 during the pregnancy undergoing or not undergoing separation. Main Outcome: Rate of exclusive breastfeeding at 6 months of age was the primary outcome. The rate of mother–infant transmission of SARS-CoV-2 infection, growth, incidence of acute infections and neurodevelopment up to 12 months of life were also evaluated. Results: In total, 60 mother–infant dyads (maternal age 30.6 vs. 33.8 years, p = 0.335; gestational age 39.0 vs. 38.9 weeks, p = 0.451) were enrolled at delivery, and 53 dyads completed the study at the 6-month follow-up. Baseline clinical characteristics were similar between the two cohorts. At 6-month follow-up, the rate of breastfeeding was significantly decreased in Cohort A compared with Cohort B (4% vs. 46%, p < 0.001). The rate of SARS-CoV-2 infection was similar between the two cohorts of the study. Weight gain at 6 months of life was significantly higher in Cohort A compared to Cohort B (8129 g, 95% CI, 7562 to 8695; vs. 7393 g, 95% CI, 6912 to 7874; p = 0.005). No differences were detected in terms of rate of acute neonatal infections and neurodevelopment outcomes. Conclusions: The separation practice led to a reduction in the rate of breastfeeding after discharge and to a consequently increased implementation of formula milk, which might justify the alarming increased weight gain of newborns who did not undergo the Rooming-In practice. Given the potential of recurrent outbreaks of other viral pandemics, our results suggest more caution early in life towards the disruption of consolidated procedures that may have long-term consequences. However, the COVID-19 pandemic offered a unique context to observe the effects of temporary mother–infant separation; clinicians should be reassured that the temporary separation practice did not affect neurodevelopment and be aware that it could be considered an option, at least if Rooming-In cannot be carried out due to severe reasons such as lack of staff or adequate space. Full article

Toxoplasmosis is a globally prevalent zoonotic parasitic disease. Neonates with congenital infection can develop severe long-term sequelae, which can be mitigated or prevented through early diagnosis and therapeutic approaches. In this context, the main objective of this study was to describe the main treatments and evaluate the effectiveness of the current treatment protocols for gestational and congenital toxoplasmosis to prevent vertical transmission and to reduce clinical manifestations in neonates. This systematic review with a meta-analysis searched digital databases (PUBMED, SCOPUS, WEB OF SCIENCE, EMBASE, and COCHRANE) for observational cohort studies published between 1 January 2013 and 29 January 2025, evaluating treatment effectiveness in gestational and congenital toxoplasmosis. Risk ratios (RRs) were calculated using random effects models to assess infection risk and clinical manifestations in neonates. The study quality was assessed following the Joanna Briggs Institute protocol and fifty-six studies from 16 countries were included, comprising 11,090 pregnant women and 4138 children. Studies were predominantly from Brazil (38%), France, and Italy. Only 9% of the studies indicated knowledge of the serological status of the pregnant woman before the gestational stage. Of 10,148 women with confirmed toxoplasmosis, 8600 received treatment, with 18% of their children infected, compared to a 58% infection rate in untreated mothers’ children. Meta-analysis showed that treatment reduced infection risk (RR = 0.34 [0.21; 0.57]) and clinical manifestations (RR = 0.30 [0.17; 0.56]). While spiramycin or triple therapy showed similar effects, triple therapy demonstrated more consistent results (RR: 0.22 [0.15; 0.32]) compared to spiramycin alone (RR: 0.54 [0.06; 4.67]). In conclusion, treatment protocols for congenital or gestational toxoplasmosis have proven to be effective in reducing the risk of infection and clinical manifestations in neonates. Regarding the type of treatment, although they have similar responses, the use of triple therapy shows more consistent responses than isolated spiramycin. It can be also concluded that prevention and mitigation of congenital toxoplasmosis require standardized treatment protocols, improved diagnostic methods, and educational programs for women of childbearing age, as treatment initiation timing and protocol choice are crucial factors in determining outcomes. Full article

Early-onset sepsis (EOS) remains a major cause of neonatal morbidity and mortality worldwide, with significant differences in the incidence and outcome of the disease in Europe. Eastern European countries face particular challenges due to differences in access to healthcare, diagnostic facilities, and prevention strategies. This review summarizes the results of recent research to provide insights into maternal risk factors, regional inequalities in access to healthcare, diagnostic biomarkers, pathogen patterns, and treatment protocols for EOS. This review also examines how healthcare infrastructure and socioeconomic factors influence EOS outcomes in Eastern Europe. Introduction: Early-onset sepsis (EOS) presents a significant health challenge for newborns, characterized by sepsis occurring within the first 72 h of life, primarily caused by the vertical transmission of pathogens from mother to child. Despite advancements in medical care, EOS remains particularly burdensome in resource-poor settings, especially in Eastern Europe, where disparities in healthcare access and maternal health are pronounced. This systematic review aims to provide insights into maternal risk factors, regional inequalities in healthcare access, diagnostic biomarkers, pathogen patterns, and treatment protocols for EOS. Background/Objectives: EOS is increasingly recognized as a public health issue, with outcomes significantly influenced by maternal health, socioeconomic status, and healthcare infrastructure. The review seeks to summarize the existing literature on EOS, particularly focusing on differences between high-income Western and low-resource Eastern European countries. The influence of maternal access to antenatal care, pathogen prevalence, and antibiotic resistance on EOS outcomes across regions will also be examined. Methods: To achieve the review’s objectives, a comprehensive search was conducted across multiple databases including PubMed, Google Scholar, ScienceDirect, and Scopus, adhering to PRISMA guidelines for systematic reviews. The inclusion criteria encompassed studies published within the last 20 years (January 2004–August 2024) that addressed EOS in late preterm or term infants, emphasizing maternal health, risk factors, diagnostic approaches, and treatment protocols pertinent to European populations. Exclusion criteria included non-English publications and studies lacking a focus on maternal and neonatal health. A total of 29 peer-reviewed articles meeting the specified criteria were ultimately included in the analysis. Results: The findings highlight significant regional disparities in EOS management between Western and Eastern Europe. Key issues include maternal risk factors, socioeconomic barriers to healthcare, diagnostic biomarkers, and pathogen resistance trends. Limited access to prenatal screenings and healthcare infrastructure in Eastern European countries, especially in rural regions in Romania, exacerbate the challenges faced by expectant mothers. Financial burdens, such as high out-of-pocket expenses, were shown to further restrict access to necessary maternal care. Conclusions: This systematic review emphasizes the urgent need for targeted investments in maternal healthcare infrastructure in Eastern Europe to mitigate the impacts of EOS. Enhanced screening programs, standardized surveillance systems, and ensuring equitable health policies are essential to improving neonatal outcomes. Additionally, tailored education and awareness campaigns for disadvantaged groups and comprehensive health policy reforms, including universal antenatal care and Group B Streptococcus (GBS), are essential to bridging healthcare gaps. Full article

During pregnancy, primary Toxoplasma gondii infection can cause congenital toxoplasmosis (CT). We described the newborns’ outcomes from a multicentre cohort of mothers with seroconversion (SC) at different gestational ages. This retrospective observational study (from 2007 to 2018) was conducted in two Italian referral hospitals: Fondazione IRCCS Policlinico San Matteo in Pavia and Spedali Civili in Brescia. In total, 247 pregnant women were enrolled: seroconversions were enrolled: seroconversions documented as having occurred in the two months preceding pregnancy in 12 cases (4.9%; 95% CI 2.2–7.5%), and during pregnancy in 235 cases (95.1%; 95% CI 92.5–97.8%). SC is defined as the appearance of specific anti-Toxoplasma antibodies (IgM/IgG) during pregnancy in a previously seronegative woman. A total of 56 (22.5%; 95% CI 17.3–27.7%) newborns were lost to follow-up; thus, the outcome of 193 (77.5%; 95% CI 72.3–82.7%) newborns was analyzed. The overall transmission rate of T. gondii infection was 23.8% (95% CI 17.8–29.8%), 0% (95% CI 0.0–11.9%) among the 1st trimester SCs, 12.5% (95% CI 5.6–19.4%) among the 2nd trimester SCs, 53.8% (95% CI 41.7–66.0%) among the 3rd trimester ones. No CT were found in the group of periconceptional infection. Among the infected newborns, clinically manifest cases were 12 (26.1%; 95% CI 13.4–38.8%), including 1 case (2.2%; 95% CI 2.0–6.4%) of stillbirth and 11 symptomatic neonates (23.9%; 95% CI 11.6–36.2%). A total of 83 amniocentesis were performed (33.6%; 95% CI 27.7–39.5%), no complication was recorded and no false positive or false negative results were registered. The results are in line with the fetal risks reported in literature for T. gondii infection during pregnancy, even if at a lower percentage probably due to a prompt treatment. Full article

This study aimed to scrutinize variations in the intestinal microbiota of neonatal dogs born through natural birth versus elective cesarean section, focusing on evaluating the influence of vaginal seeding on the microbiota of cesarean-born neonates. Samples were collected from cesarean-sectioned females before anesthesia and from naturally birthing females during prodrome signs, along with neonates at eight time points from birth to 15 days of age. In the cesarean section group, seeding was performed in half of the neonates (cesarean section seeding group; seeding consisted of gently rubbing the gauze, obtained from the mother’s vagina, onto the mouths, faces, and bodies of the newborns), while the other half underwent microbiological sample collection without seeding (cesarean section group). Another group (normal birth group) consisted of naturally born neonates. Microbiota analysis included counting for enterobacteria, Staphylococcus spp., and Streptococcus spp. The results suggested that vertical transmission played a crucial role, but the method of birth did not emerge as the primary determinant of observed differences. Under study conditions, vaginal seeding failed to effectively modulate the microbiota of neonates born through elective cesarean section. Further investigations into the gut–brain axis are suggested for understanding factors influencing the initial development of the canine intestinal microbiota in neonates born through different delivery routes. Full article

Understanding perinatal health outcomes following SARS-CoV-2 infection during pregnancy necessitates large-scale studies of mother-infant dyads. Hospital-based studies of pregnant women and their neonates provide valuable insights within the field of perinatal health research. The aim of this study was to evaluate the effect of SARS-CoV-2 infection on maternal and perinatal outcomes among hospitalized pregnant women in Rio de Janeiro during the COVID-19 pandemic. Methods: The study consisted of a time-to-event analysis of a hospital-based cohort of 1185 pregnant women ≥ 16 years and their infants from May 2020 to March 2022. Pregnant women were classified as infected if they had a SARS CoV-2 positive RT-PCR or a positive rapid antigen test. An exploratory analysis of qualitative variables was conducted with calculation of absolute and relative frequencies and calculation of 95% confidence intervals. Survival functions were estimated by the Kaplan–Meier method, and the Cox proportional hazards model was employed to interpret the effects of SARS-CoV-2 infection on time to adverse maternal and perinatal outcomes, adjusted for vaccination, comorbidity, and gestational trimester. Results: A total of 21% (249/1185) women were infected with SARS-CoV-2, with a median age of 26 (range: 16–47). Cesarean section deliveries were performed in 57% (135/237) SARS CoV-2+ participants vs. 43% (391/914) of uninfected participants, p < 0.001. Intensive care unit admission and/or death occurred in 68 of 1185 participants (5.7%), 44 of 249 participants (17.7%) infected with SARS CoV-2 vs. 24 of 936 uninfected participants (2.5%). All 21 participants who died were unvaccinated against COVID-19. Women infected with SARS-CoV-2 were at greater risk of adverse maternal outcomes (crude HR: 5.93, 95% CI: 3.58–9.84; adjusted HR: 5.47, 95% CI: 3.16–9.48) than uninfected pregnant women. SARS CoV-2 vertical transmission was observed in 6 of 169 (3.6%) tested neonates. Preterm deliveries occurred more frequently in patients testing positive for SARS-CoV-2 (30.7% vs. 23.6). In the survival analysis, no effect of SARS-CoV-2 infection was observed on prematurity (HR: 0.92, 95% CI: 0.68–1.23) and adverse perinatal outcomes, including fetal distress (HR: 1.29, 95% CI: 0.82–2.05), stillbirth (HR: 1.07, 95% CI: 0.48–2.38), and neonatal death (HR: 0.96, 95% CI: 0.35–2.67), even after adjusting for vaccination, comorbidity, gestational trimester, and periods of time. Conclusion: The risk of maternal death due to COVID-19 highlights the need for adequate preventive measures, particularly vaccination, during the prenatal and postpartum periods. Full article

Archaea have been identified as early colonizers of the human intestine, appearing from the first days of life. It is hypothesized that the origin of many of these archaea is through vertical transmission during breastfeeding. In this study, we aimed to characterize the archaeal composition in samples of mother-neonate pairs to observe the potential vertical transmission. We performed a cross-sectional study characterizing the archaeal diversity of 40 human colostrum-neonatal stool samples by next-generation sequencing of V5–V6 16S rDNA libraries. Intra- and inter-sample analyses were carried out to describe the Archaeal diversity in each sample type. Human colostrum and neonatal stools presented similar core microbiota, mainly composed of the methanogens Methanoculleus and Methanosarcina. Beta diversity and metabolic prediction results suggest homogeneity between sample types. Further, the co-occurrence network analysis showed associations between Archaea and Bacteria, which might be relevant for these organisms’ presence in the human milk and neonatal stool ecosystems. According to relative abundance proportions, beta diversity, and co-occurrence analyses, the similarities found imply that there is vertical transmission of archaea through breastfeeding. Nonetheless, differential abundances between the sample types suggest other relevant sources for colonizing archaea to the neonatal gut. Full article