Perinatal or early-postnatal cytomegalovirus infection in preterm infants under 34 weeks gestation born to CMV-seropositive mothers within a high-seroprevalence population

Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Routine breast milk monitoring using automated molecular assay system reduced postnatal CMV infection in preterm infants

Human cytomegalovirus (CMV) transmitted through breast milk poses fatal risks to preterm infants. However, current molecular assay systems often do not accommodate breast milk samples. In this study, we evaluated the analytical and clinical performance of the measurement procedure of CMV load in breast milk utilizing the Cobas CMV test on the Cobas 6,800 system. This was enabled by incorporating a simple independent sample preparation procedure before the application of samples on the automated assay system. Clinical data from electronic medical records were retrospectively analyzed. Breast milk samples from mothers of preterm infants born before 33 weeks of gestation were screened for CMV using the automated assay system. CMV positivity rates in breast milk and neonatal samples and the CMV transmission rate were calculated. Furthermore, to validate the analytical accuracy of the overall measurement procedure with newly obtained residual breast milk samples, the linearity of the measurement procedure was assessed, and a simplified sample preparation method was validated against a conventional method. The CMV positivity rates in maternal breast milk and neonatal samples were 57.8 and 5.2%, respectively. The CMV transmission rate through breast milk was 7.7%. No significant differences in gestational age or birth weight were found between the CMV-negative and CMV-positive neonates. The linearity of the procedure was observed within a range of 1.87-4.73 log IU/mL. The simplified sample preparation method had an equivalent or even improved CMV detection sensitivity than the conventional method. Incorporating a simple independent sample preparation procedure effectively resolved any potential issues regarding the application of breast milk on the automated assay system. Our approach contributed to reduced vertical transmission of CMV by providing a convenient and reliable method for the monitoring of breast milk CMV positivity for clinicians.

Transmission of cytomegalovirus via breast milk in low birth weight and premature infants: a systematic review and meta-analysis

Background

This study aimed to investigate the transmission of cytomegalovirus (CMV) via breast milk in low birth weight (LBW) and premature infants and its effects.

Methods

PubMed, Medline, Cochrane Library, and Embase were searched for studies (without language and time restriction) published before March 27, 2020, that examined the effect of CMV transmitted by breast milk on LBW and premature infants. The rates of breast milk-acquired CMV infection, CMV-related symptoms, and CMV-related sepsis-like syndrome (CMV-SLS) in LBW and premature infants were pooled from each study.

Results

Eighteen studies with 1920 LBW and premature infants were included. The pooled CMV infection rate from breast milk for infants fed untreated breast milk was significantly higher than those fed frozen breast milk [19.3, 95% confidence interval (CI) = 11.8–29.9% vs. 13.5, 95% CI = 8.0–22.0%, P < 0.01). Similarly, the pooled CMV infection rate for infants fed untreated breast milk was significantly higher than those with mixed feeding (P < 0.0001). The mixed feeding group had a significantly lower rate of CMV-related symptoms than the other groups (2.4%, P < 0.01).

Conclusions

These findings suggested a higher CMV infection rate in LBW or premature infants fed untreated breast milk than other feeding groups. Studies on the long-term outcomes of CMV infection transmitted from breast milk are needed to address the optimal feeding practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02984-7.

Transmission of cytomegalovirus in fresh and freeze-thawed mother's own milk to very preterm infants: a cohort study

OBJECTIVES

The objectives of the study were to clarify: (i) the frequency of human cytomegalovirus (HCMV) transmission, (ii) the association between the viral load in mother's own milk (MOM), the amount of fresh MOM and transmission, and (iii) the frequency of sepsis-like-symptoms (SLS) among infants born to seropositive mothers compared to infants born to seronegative mothers.

STUDY DESIGN

This prospective cohort study enrolled very preterm infants (gestational age <32 weeks) from Denmark. Weekly samples of fresh MOM and urine were analyzed for HCMV-DNA.

RESULTS

Twenty-six very preterm infants were enrolled. Four acquired an HCMV infection, of which two developed SLS. HCMV-infected infants received MOM with a significant higher viral load compared to the HCMV-uninfected infants.

CONCLUSION

A combination of a high viral load and an increased amount of fresh MOM increased the risk of HCMV transmission. SLS was only slightly more common among infants exposed to HCMV positive MOM.

New short-term heat inactivation method of cytomegalovirus (CMV) in breast milk: impact on CMV inactivation, CMV antibodies and enzyme activities

OBJECTIVES

Breast milk (BM) is the primary source of cytomegalovirus (CMV) transmission to premature infants with potentially harmful consequences. We therefore wanted to evaluate temperature and duration of short-term BM pasteurisation with respect to CMV inactivation, effect on CMV-IgG antibodies and BM enzyme activities.

METHODS

116 artificially CMV-spiked BM and 15 wild-type virus-infected samples were subjected for 5 s to different temperatures (55°C-72°C). CMV-IE-1 expression in fibroblast nuclei was assessed using the milk whey fraction in short-term microculture. BM lipase and alkaline phosphatase (AP) activities and CMV binding using CMV-recomLine immunoblotting and neutralising antibodies using epithelial target cells were analysed before and after heating.

RESULTS

A minimum of 5 s above 60°C was necessary for CMV inactivation in both CMV-AD-169 spiked and wild-type infected BM. Lipase was very heat sensitive (activities of 54% at 55°C, 5% at 60°C and 2% at 65°C). AP showed activities of 77%, 88% and 10%, respectively. CMV-p150 IgG antibodies were mostly preserved at 62°C for 5 s.

CONCLUSION

Our results show that short-term pasteurisation of BM at 62°C for 5 s might be efficient for CMV inactivation and reduces loss of enzyme activities, as well as CMV binding, and functional CMV antibodies.

Human Breast Milk-acquired Cytomegalovirus Infection: Certainties, Doubts and Perspectives

Breast Milk (BM) is the best source of nutrition for newborns, especially if premature. In fact, its beneficial impact on short- and the long-term neonatal outcome has was deeply described. Unfortunately, BM could not be always so safe, especially due to the possible presence of maternal viruses that can be shed and transferred to the breastfed neonate. Among these, Cytomegalovirus (CMV) can potentially lead to a serious and acute illness, mostly in case of low gestational age. Some studies also report the association of CMV-acquired infection to an increased risk of structural and functional brain modifications and neurological impairment. Due to these reasons, a strategy to remove CMV from BM with a minimal or absent impact on its beneficial components would be desirable. Up to now, pasteurization, freezing, ultraviolet- C or microwave irradiation are the available techniques; they show different levels of efficacy and variable effects on BM composition, even if many studies are still needed to fully clarify these implications. In this review, we provide an update of the current evidence about these topics. We focus on the factors promoting CMV shedding through BM; moreover, the possible occurrence of a severe disease in preterm neonates is also described. Finally, we investigate the potential effects showed on BM properties by the strategies that prevent or reduce viral transmission, therefore influencing newborns' health, and the new techniques which could show a relevant role in the next future, such as metabolomics.

Nutrition of Preterm Infants and Raw Breast Milk-Acquired Cytomegalovirus Infection: French National Audit of Clinical Practices and Diagnostic Approach

Raw breast milk is the optimal nutrition for infants, but it is also the primary cause of acquired cytomegalovirus (CMV) infection. Thus, many countries have chosen to contraindicate to feed raw breast milk preterm infants from CMV-positive mothers before a corrected age of 32 weeks or under a weight of 1500 g. French national recommendations have not been updated since 2005. An audit of the French practices regarding the nutrition with raw breast milk in preterm infants was carried out using a questionnaire sent to all neonatal care units. Diagnosed postnatal milk-acquired CMV infections have been analysed using hospitalisation reports. Seventy-five percent of the neonatal units responded: 24% complied with the French recommendations, 20% contraindicated raw breast milk to all infants before 32 weeks regardless of the mothers' CMV-status, whereas 25% fed all preterm infants unconditionally with raw breast milk. Thirty-five cases of infants with milk-acquired CMV infections have been reported. The diagnosis was undeniable for five patients. In France, a high heterogeneity marks medical practices concerning the use of raw breast milk and the diagnostic approach for breast milk-acquired CMV infection is often incomplete. In this context, updated national recommendations and monitored CMV infections are urgently needed.

Congenital and perinatally-acquired infections in resource-constrained settings

INTRODUCTION

Congenital and perinatal infections are a leading cause of neonatal and infant morbidity and mortality. Maternal screening, vaccines or treatment where available, constitute effective prevention strategies to reduce the burden of these diseases. Data on the burden of congenital and perinatal infections are very limited for low and middle-income regions.

AREAS COVERED

This review aims to summarize the burden of congenital and perinatal infections and the main challenges for their control in resource-limited settings. Articles were identified through the main electronic databases and cover the period 1971-2016. Expert commentary: Estimates from low and middle-income countries indicate that the burden of congenital infections may be higher in these regions than in industrialized countries. As preventive and curative strategies are available to tackle some of these infections, efforts at the international and national levels must be made to implement those and thus reduce their burden in resource-limited countries.

Prevention of Cytomegalovirus Transmission via Breast Milk in Extremely Low Birth Weight Infants

PURPOSE

Extremely low birth weight infants (ELBWIs) have a high risk of acquiring cytomegalovirus (CMV) infection via breast milk and consequently developing serious symptoms. We evaluated whether freeze-thawing or pasteurization could prevent postnatal CMV infection transmitted through breast milk in ELBWIs.

MATERIALS AND METHODS

Medical records of 385 ELBWIs with whole milk feeding, and freeze-thawed or pasteurized breast milk feeding were reviewed retrospectively. Postnatally acquired CMV infection was defined as an initial negative and a subsequent positive on follow-up urine CMV DNA polymerase chain reaction screening tests. The incidence, clinical characteristics, symptoms, sequelae, and long-term outcome at corrected age [(CA): 2 years of CMV infection] were analyzed.

RESULTS

While no infant developed CMV infection with whole milk (0/22) or pasteurized breast milk (0/62) feeding, postnatal CMV infection was diagnosed in 8% (27/301) of ELBWIs who were fed freeze-thawed breast milk. Gestational age in the CMV group was significantly lower than the control group. In 82% (22/27) of cases, CMV infection was symptomatic and was associated with increased ventilator days and ≥moderate bronchopulmonary dysplasia (BPD). Neurodevelopmental outcome and growth status at CA 2 years were not different between the study groups. Lower gestational age and freeze-thawed breast milk feeding >60% of total oral intake during the first 8 postnatal weeks were independent risk factors for acquiring postnatal CMV infection. BPD (≥moderate) was the only significant adverse outcome associated with this CMV infection.

CONCLUSION

Pasteurization but not freeze-thawing of breast milk eradicated the postnatal acquisition of CMV infection through breast milk.

Cytomegalovirus infection and neonatal outcome in extremely preterm infants after freezing of maternal milk

BACKGROUND

Cytomegalovirus (CMV) infection acquired from breast milk can cause serious illness in extremely preterm (EPT) infants (<28 weeks). Some neonatal centers freeze maternal milk (MM) to prevent CMV transmission; however, this practice is controversial. In this study, we assessed the CMV transmission rate and neonatal outcome in EPT infants after routine freezing of all MM.

METHODS

EPT infants (n = 140) and their mothers were randomized to the intervention group (only freeze-thawed MM) or the control group (combined fresh and freeze-thawed MM). Freeze-thawed MM was frozen at -20°C for ≥3 days before thawing. Mothers had serological tests for CMV, and MM was analyzed for CMV by polymerase chain reaction and CMV culture. Infants underwent CMV screening with urine analysis by CMV-polymerase chain reaction and CMV culture until 12 weeks of age.

RESULTS

Congenital CMV infection was detected in 2% of screened infants. The CMV transmission rate in infants fed with CMV-DNA positive milk was 8% (3 of 37) in the intervention group and 6% (2 of 33) in controls. All infants infected by CMV were asymptomatic. The final per-protocol analysis included 56 infants in the intervention group and 65 controls. Neonatal mortality was comparable between the groups (7% vs. 6%). Neonatal morbidity was similar, except for late onset Candida sepsis, which was more frequent in the controls (12% vs. 0%).

CONCLUSIONS

Routine freezing of all MM did not affect the rate of CMV transmission but may help to prevent fungal sepsis in EPT infants. This observation merits further investigation.

Pasteurization of breastmilk decreases the rate of postnatally acquired cytomegalovirus infections, but shows a nonsignificant trend to an increased rate of necrotizing enterocolitis in very preterm infants--a preliminary study

AIM

This study assessed whether feeding preterm infants unpasteurized breastmilk (1) decreases the rate of late-onset sepsis and necrotizing enterocolitis and (2) increases the rate of postnatally acquired cytomegalovirus infections.

SUBJECTS AND METHODS

Between January 2008 and July 2013, preterm infants below 32 completed weeks of gestational age admitted to the neonatal intensive care unit of Innsbruck Medical University (Innsbruck, Austria) (n=344) were eligible for the study. Of those, 323 fed breastmilk were retrospectively enrolled in the study. Two groups were formed, with 164 infants being fed unpasteurized and 159 infants being fed pasteurized breastmilk.

RESULTS

There was no significant difference in the rate of late-onset sepsis or necrotizing enterocolitis between the unpasteurized and pasteurized breastmilk groups (late-onset sepsis, 15.9% versus 15.1% [p=0.486]; necrotizing enterocolitis, 2.4% versus 4.4% [p=0.254]). The number of infants diagnosed with postnatally acquired cytomegalovirus infection was significantly higher in the unpasteurized group (39.3%) compared with the pasteurized group (4.2%) (p=0.008).

CONCLUSIONS

Feeding preterm infants unpasteurized breastmilk increases the rate of postnatally acquired cytomegalovirus infections. However, we also demonstrate a nonsignificant trend to a decreased rate of necrotizing enterocolitis in the unpasteurized group, which needs to be confirmed in larger studies.

Infectious causes of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency among premature infants. Although a large body of research has focused on understanding its pathogenesis, the exact mechanism has not been elucidated. Of particular interest is the potential causative role of infectious culprits in the development of NEC. A variety of reports describe bacterial, viral, and fungal infections occurring in association with NEC; however, no single organism has emerged as being definitively involved in NEC pathogenesis. In this review, the authors summarize the literature on infectious causes of NEC.

Characterization of human breast milk leukocytes and their potential role in cytomegalovirus transmission to newborns

BACKGROUND

Breast milk is the primary source of cytomegalovirus (CMV) transmission to newborns and premature infants. The role of cell-free milk whey in virus transmission is well understood, yet the knowledge about the role of milk cells in this process is scarce.

OBJECTIVE

To preliminarily characterize different breast milk cell types during various stages of lactation to evaluate their potential role in the transmission of CMV.

MATERIALS AND METHODS

Breast milk cells of 18 lactating and 3 CMV-seropositive mothers of preterm infants were isolated and characterized for expression of myeloid markers by flow cytometry. In parallel, cytospin preparations were stained with α-naphthyl acetate esterase to identify milk macrophages and describe the dynamic changes of the macrophage-granulocyte population during lactation. The influence of different time points of lactation was analyzed by FACS analysis of double-stained (CD15/CD66b) milk cells. To characterize CMV target cells in breast milk, we enriched CD14+ cells by MACS (Miltenyi) and monitored cell fractions using CMV IEEx4 nested PCR and pp67 CMV RNA by NASBA.

RESULTS

Virolactia, viral DNAlactia, and viral pp67 late mRNA could be detected in breast milk cells only in defined time periods. Granulocytes and macrophages demonstrated an inverse dynamic with neutrophils predominating in the early stages (<30 days postpartum) and macrophages in later stages (>60 days postpartum) of lactation. Enrichment of CD14-positive cells resulted in viral DNA and pp67 late mRNA detection.

CONCLUSIONS

Granulocytes and monocytes/macrophages are the predominating cell populations in breast milk with changing frequencies during early lactation. These results demonstrate that CD14-positive breast milk cells seem to be one of the target cells for CMV in breast milk.

Breast milk-acquired cytomegalovirus infection and disease in VLBW and premature infants

BACKGROUND

Very low birth weight (VLBW) and premature infants are at risk for developing postnatal cytomegalovirus (CMV) disease, including CMV-related sepsis-like syndrome (CMV-SLS) for which estimates [corrected] in the United States are lacking.

METHODS

We performed a systematic review and meta-analysis to estimate the pooled proportions (and 95% confidence intervals) of VLBW and premature infants born to CMV-seropositive women with breast milk-acquired CMV infection and CMV-SLS. We combined these proportions with population-based rates of CMV seropositivity, breast milk feeding, VLBW, and prematurity to estimate annual rates of breast milk-acquired CMV infection and CMV-SLS in the United States.

RESULTS

In our meta-analysis, among 299 infants fed untreated breast milk, we estimated 19% (11%-32%) acquired CMV infection and 4% (2%-7%) developed CMV-SLS. Assuming these proportions, we estimated a rate of breast milk-acquired CMV infection among VLBW and premature infants in the United States of 6.5% (3.7%-10.9%) and 1.4% (0.7%-2.4%) of CMV-SLS, corresponding to 600 infants with CMV-SLS in 2008. Among 212 infants fed frozen breast milk, our meta-analysis proportions were 13% (7%-24%) for infection and 5% (2%-12%) for CMV-SLS, yielding slightly lower rates of breast milk-acquired CMV infection (4.4%; 2.4%-8.2%) but similar rates of CMV-SLS (1.7%; 0.7%-4.1%).

CONCLUSIONS

Breast milk-acquired CMV infection presenting with CMV-SLS is relatively rare. Prospective studies to better define the burden of disease are needed to refine guidelines for feeding breast milk from CMV-seropositive mothers to VLBW and premature infants.

Cytomegalovirus infection in infants admitted to a neonatal intensive care unit

OBJECTIVES

To determine the incidence of congenital cytomegalovirus (CMV) infection and the frequency of postnatal infection in a neonatal intensive care unit (NICU).

METHODS

Urine samples of 135 infants who were admitted to the NICU during a 6 month period were evaluated to detect CMV using a nested PCR assay. A breast milk sample was obtained to determine viral excretion. Clinical characteristics of infected and non-infected infants were compared.

RESULTS

Congenital CMV infection was confirmed in two (1.48%) infants. Post-natal infection was documented in four of 36 (11.1%) infants that were evaluated. CMV excretion was detected in 43 of 116 mothers. Gestational age of infants born to mothers who excreted CMV was shorter than that of infants of mothers with negative results (33.1 versus 34.2 weeks; p = 0.07).

CONCLUSIONS

CMV excretion in breast milk is frequent and is associated to congenital and postnatal infection. Further studies are necessary to assess the impact of CMV infection during pregnancy and neonatal outcomes.

Sero-epidemiological survey of human cytomegalovirus-infected children in Weifang (Eastern China) between 2009 and 2012

Background

To understand the prevalence and characteristics of human cytomegalovirus (HCMV) infection in children in the Weifang area, and to provide information for its prevention and treatment.

Methods

A comprehensive survey was performed from 2009 to 2012 in 7582 children from birth to 6 years of age hospitalized in the Maternity and Child Health Hospital of Weifang. ELISA HCMV serology results and survey data were analyzed by age group and socio-economic level. The infection rates were based on IgG and IgM serology.

Results and conclusions

The overall infection rate from IgG and IgM in the Weifang area from 2009 to 2012 was 42.5% (3496/7582), among which 34.2% were HCMV-IgG positive, suggesting past infection. Overall, the probability of active HCMV infection showed no gender difference in any age group (P >0.05). Recent infections centered on the first 6 months of life, presumably due to breastfeeding. Among the 654 children hospitalized for active HCMV infection, 379 (57.9%) were from rural areas and 275 (42.1%) from urban areas, showing that active infection in the countryside was higher than that in the city (χ² = 32.65, p <0.01).

The effect of prenatal highly active antiretroviral therapy on the transmission of congenital and perinatal/early postnatal cytomegalovirus among HIV-infected and HIV-exposed infants

BACKGROUND

Before highly active antiretroviral therapy (HAART), congenital cytomegalovirus (CMV) rates were higher among human immunodeficiency virus (HIV)-exposed infants than unexposed infants. This study examines congenital and perinatal/early postnatal (P/EP) CMV among HIV-exposed infants pre- and post- HAART.

METHODS

Infants born to HIV-infected women were evaluated for congenital CMV (CMV-positive culture in first 3 weeks of life) and P/EP CMV (positive culture in first 6 months of life). Prenatal maternal HAART was defined as triple antiretroviral therapy (ART) with at least 1 nonnucleoside reverse-transcriptase inhibitor or protease inhibitor.

RESULTS

Among 414 infants evaluated, 1678 CMV assessment days were completed (mean = 3 assessment days per infant). Congenital CMV rates did not differ by time period, HAART use, or infant HIV infection status. P/EP CMV rates were greater for the 1988-1996 birth cohort (17.9%) compared with the 1997-2002 birth cohort (8.9%) (P < .01), HIV-infected versus uninfected infants (P < .01), and infants with no maternal ART versus those with ART (P < .01). Controlling for potential confounders, P/EP CMV was associated with no maternal ART (odds ratio = 4.7; P < .01), and among those with no maternal ART, P/EP CMV was associated with maternal CD4 count ≤200 cells/μL (P < .01). For HIV-uninfected infants with P/EP CMV, symptoms including splenomegaly, lymphadenopathy, and hepatomegaly were associated with no maternal HAART versus those with HAART (41% vs 6%; P < .05).

CONCLUSIONS

Although congenital CMV rates did not change, the post-HAART era showed reduced P/EP CMV and occurrence of related clinical symptoms. These findings underscore the importance of prenatal HAART for all HIV-infected pregnant women.

Transmission of cytomegalovirus via breast milk to the prematurely born infant: a systematic review

To analyse current data on transmission of human cytomegalovirus (HCMV) via breast milk with subsequent symptomatic HCMV infection of the preterm infant and to report on long-term follow-up, a systematic literature review was performed using EMBASE, MEDLINE and CINAHL (January 1966 to December 2008) Studies were included for analysis if congenital HCMV infection was excluded and transmission via breast milk was either confirmed or strongly suspected. Twenty-six studies were included for analysis. Maternal HCMV-IgG-positivity was reported to be in the range 51.6-100% (median 81.6%), HCMV-IgG detection in breast milk in the range 67-97.2% (median 80%) and HCMV-positivity of the infants in the range 5.7-58.6%. Symptomatic HCMV disease occurred in 0-34.5% (median 3.7%) and severe sepsis-like syndrome in 0-13.8% (median 0.7%). Data on long-term outcome of preterm infants with symptomatic HCMV infection revealed a low risk for mild neurological and cognitive sequelae, without hearing impairment. Recommendations for high-risk preterm infants diverged markedly. The current data report low rates of symptomatic disease after transmission of HCMV via breast milk to the preterm infant without evidence of certain long-term sequelae. The results of our review do not support a general approach, either by avoidance or pasteurization of breast milk, in high-risk preterm infants.

Prevention of maternal cytomegalovirus infection: current status and future prospects

Human cytomegalovirus (CMV) infection is the most common cause of perinatal viral infection in the developed world, resulting in approximately 40,000 congenitally infected infants in the United States each year. Congenital CMV infection can produce varying degrees of neurodevelopmental disabilities. The significant impact of congenital CMV has led the Institute of Medicine to rank development of a CMV vaccine as a top priority. Vaccine development has been ongoing; however no licensed CMV vaccine is currently available. Treatment of pregnant women with CMV hyperimmune globulin has shown promising results, but has not been studied in randomized controlled trials. Education on methods to prevent CMV transmission, particularly among young women of child-bearing age, should continue until a CMV vaccine becomes available. The epidemiology, clinical manifestations, prevention strategies, and treatment of CMV infections are reviewed.

[Review and guidelines on the prevention, diagnosis and treatment of post-natal cytomegalovirus infection]

Postnatal cytomegalovirus (CMV) infection in the newborn can occur from exposure to maternal cervical secretions during birth, ingestion of breast milk, transfusion of blood products or transmission by body fluids of infected people. Breast milk is the main source of infection, given the high rate of CMV-positive mothers excreting CMV in milk. Freezing reduces the risk of CMV transmission by breastfeeding, although it does not eliminate it completely. Pasteurisation prevents such transmission, but it can alter the immunological properties of breast milk. Postnatal CMV infection is usually asymptomatic, as it normally results from viral reactivation in the mother, and the neonate is born with protective antibodies. However, in the very low birth weight premature infant the amount of transferred antibodies is smaller and a symptomatic infection can occur. Symptomatic post-natal CMV infection in the newborn typically causes hepatitis, neutropenia, thrombocytopenia or sepsis-like syndrome. Pneumonitis and enteritis are less common, but very characteristic. Diagnosis is based on urine virus detection at the time of onset of symptoms. Postnatal CMV infection in the newborn generally resolves spontaneously without antiviral treatment. Ganciclovir should be reserved for severe cases. Unlike congenital CMV disease, post-natal CMV infection in the preterm infant does not seem to be associated with hearing loss or abnormal neuro-development in long term follow-up.

A haemophagocytic lymphohistiocytosis (HLH)-like picture following breastmilk transmitted cytomegalovirus infection in a preterm infant

Due to septic illness, neutro- and thrombocytopenia, blocked myelopoiesis, CMV-positive breast milk and CMV-pp65 antigen in bone marrow mononuclear cells, CMV-related HLH was presumed in a breast fed neonate (gestational age 24 weeks). Treatment was successful with foscarnet and methylprednisolone. HLH may be a complication of post-natal CMV-infection acquired from breast milk.

Cytomegalovirus transmission to preterm infants during lactation

Breastfeeding has a major impact on HCMV epidemiology. The incidence of postnatal HCMV reactivation during lactation equals the maternal seroprevalence. Infectious virus, viral DNA and RNA can be isolated easily from cell and fat-free milk whey. Early onset of viral DNAlactia and virolactia as well as high viral load in milk whey are maternal risk factors for virus transmission. The dynamics of HCMV reactivation can be described by unimodal kinetics with interindividual variation. Virus reactivation during lactation is a self-limiting local process in the absence of systemic HCMV infection. Preterm infants below 1000g birthweight and a gestational age below 30 weeks may be at high risk of acquiring a symptomatic HCMV infection. Several recent studies described low transmission rates and mostly asymptomatically infected neonates using frozen milk. Despite different freeze-storing procedures, HCMV transmissions occurred, and severe HCMV infections were observed. Few data exist on the long-term outcome of postnatally acquired HCMV infection via breast milk. To substantiate the international debate on the use of native or inactivated milk for feeding of preterm infants, additional data are necessary for better identification of mother-infant-pairs at risk for viral transmission and symptomatic infection early after birth.

Cytomégalovirus néonatal et allaitement maternel chez le nouveau-né prématuré. Quelles propositions?

In France, screening for cytomegalovirus infection (CMV) during pregnancy is not recommended in routine. The transmission of CMV through breastmilk from mothers to preterm infants is frequent (15-20%). The frequency of neuro-sensorial handicap related to congenital CMV infection in very preterm infants is not well documented. We report the case of a female infant born at 30 weeks of gestation. At 15 days, she developed cholestatic jaundice. Urine cultures were positive for CMV. Diagnostic procedure showed no other cause for jaundice. At 40 days, the infant presented with hepato-splenomegaly, purpura and abnormal skin color related to a symptomatic, secondary CMV infection, probably transmitted through breastmilk. Ganciclovir was begun for 21 days. At 12 months, she presents with normal development. This observation raises questions about breastfeeding in very preterm infants. Unexplained prematurity could reflect recent infection or reactivation in the mother. Thus, because of the well-known risks of prematurity on one hand, and CMV infection on the other, we suggest that detection of CMV seropositive mothers should be considered before allowing breastfeeding. If the mother has serologic evidence of recent infection or reactivation, freezing breastmilk at -20 degrees C for 3 days may be an option in order to reduce virolactia, especially during early lactation. This may reduce the risk of postnatal vertical virus transmission with minimal logistical difficulties and without interrupting breastfeeding.

Review and meta-analysis of the epidemiology of congenital cytomegalovirus (CMV) infection

We reviewed studies that reported results of systematic cytomegalovirus (CMV) screening on fetuses and/or live-born infants. The overall birth prevalence of congenital CMV infection was 0.64%, but varied considerably among different study populations. About 11% of live-born infants with congenital CMV infection were symptomatic, but the inter-study differences in definitions of symptomatic cases limit the interpretation of these data. Non-white race, low socioeconomic status (SES), premature birth, and neonatal intensive care unit admittance were risk factors for congenital CMV infection. Birth prevalence increased with maternal CMV seroprevalence. Maternal seroprevalence accounted for 29% of the variance in birth prevalence between study populations. Maternal seroprevalence and birth prevalence were both higher in study populations that were ascertained at birth rather than in the prenatal period. Thus, timing of ascertainment should be considered when interpreting birth prevalence estimates. Birth prevalence was inversely correlated with mean maternal age, but this relationship was not significant when controlling for maternal seroprevalence. The rate of transmission to infants born to mothers who had a primary infection or a recurrent infection during pregnancy was 32% and 1.4%, respectively. Possible maternal primary infections (i.e. seropositive mother with CMV IgM) resulted in congenital infections about 20% of the time, but are likely to represent a mixture of primary and recurrent infections. In summary, CMV is a common congenital infection worldwide that can lead to permanent disabilities. There is an urgent need for interventions that can reduce the substantial burden of this often overlooked disease.

Acquisition of human cytomegalovirus infection in infants via breast milk: natural immunization or cause for concern?

Since the recognition in the 1960s that human cytomegalovirus (HCMV) infections could be transmitted by breast milk, there has been relatively little attention paid to the potential medical consequences of such infections. Indeed, since HCMV infections acquired by healthy newborn infants appear to be largely asymptomatic in nature, there has been no real incentive to develop or implement strategies to prevent transmission by this route. However, recent studies have identified a significant risk for low-birth weight, premature infants for the development of HCMV disease following acquisition of infection via breast milk. Such infections may cause considerable short-term morbidity and, in some cases, severe, life-threatening illness. There is little consensus amongst neonatologists on the approach to prevention and management of such infections. This review summarises the epidemiology and natural history of HCMV infections acquired via breast milk, and outlines available strategies for prevention and management of such infections, as well as opportunities for future clinical research on this understudied topic.

Case-control study of symptoms and neonatal outcome of human milk-transmitted cytomegalovirus infection in premature infants

OBJECTIVE

Preterm infants are at risk of acquiring human cytomegalovirus (CMV) infection through breast milk transmission, possibly leading to serious symptoms, as suggested by previous studies. Over a period of 8.5 years, we compared infants infected postnatally with CMV with noninfected controls to determine whether CMV infection transmitted through breast milk poses serious acute risks.

STUDY DESIGN

CMV monitoring included maternal serologic testing and biweekly viral culture and polymerase chain reaction in breast milk and infant urine. Clinical and laboratory test findings were assessed retrospectively in infected infants and controls matched for gestational age during the initial hospital stay.

RESULTS

Forty CMV-infected infants met the study criteria. They had lower minimal platelet and neutrophil counts and a higher frequency of C-reactive protein (CRP) elevations to 10 to 20 mg/L than their matched controls (P < or = .001). But no association of CMV infection with bronchopulmonary dysplasia, necrotizing enterocolitis, growth, or CRP elevations to > 20 mg/L was found. Cholestasis appeared in 3 infants in the CMV-infected group, but disappeared within 10 weeks.

CONCLUSIONS

Neonatal symptoms related to postnatal CMV infection were transient and had no affect on neonatal outcome in these infants, in contrast with uncontrolled reports. Whether withholding or pasteurizing breast milk is warranted, however, depends on long-term outcome.

Breast milk as a source for acquisition of cytomegalovirus (HCMV) in a premature infant with sepsis syndrome: Detection by real-time PCR

Symptomatic disease due to human cytomegalovirus (HCMV) has been increasingly recognized in low birth weight (LBW) premature infants. Breast milk has been identified as a potential source for these infections. At approximately 60 days of life a LBW, premature infant was diagnosed with HCMV sepsis syndrome, prompting further investigation of the source for HCMV acquisition. The infant had received a combination of both fresh and frozen breast milk from his mother throughout his first 2 months of life. We utilized a real-time PCR assay for HCMV DNA to retrospectively examine viral genome copy number in serial samples of stored, frozen breast milk. This analysis indicated an increase in breast milk viral load over the first 45 days of life, heralding the HCMV sepsis syndrome that was observed clinically. Real-time PCR may be a useful tool in the evaluation of HCMV viral load in breast milk.

Transfusion-related cytomegalovirus infection among very low birth weight infants in an endemic area

This study investigated the incidence of acquired cytomegalovirus (CMV) infection in very low birth weight infants (VLBWI) given CMV seropositive blood, and sought to determine whether filtering and irradiation of blood products could help prevent CMV infection and the time required to clear passively-derived anti-CMV IgG among 80 VLBWI transfused with filtered-irradiated blood, 20 VLBWI transfused with nonfiltered- nonirradiated blood and 26 nontransfused VLBWI. CMV IgG and IgM values were obtained from all blood products prior to transfusions, and from VLBWI at birth until the infants became seronegative. Urine was obtained for CMV culture at birth and every 3-4 weeks until 12 weeks after the final transfusion. The incidence of CMV IgG seropositivity among the 126 infants at birth and the blood products given were 96% and 95%, respectively. The incidence of acquired CMV infection was 4/100 (4%) in the transfused group: 2/80 (2.5%) and 2/20 (10%) in the filtered-irradiated and nonfiltered-nonirradiated transfusion groups, respectively. Approximately 9-10 months elapsed to clear passively acquired CMV IgG. The irradiation and filtering of the blood products did not seem to decrease the transfusion-related CMV infection rate in Korea among VLBWI, however, further validation is recommended in a larger cohort of infants.

Cytomegalovirus in human breast milk: risk to the premature infant

Human cytomegalovirus (HCMV) can be transmitted through breast milk to neonates. Although healthy full-term infants rarely develop symptoms of CMV infection; premature or low-birth-weight infants can experience symptomatic infection that is occasionally severe. There is limited information on the long-term effects of postnatal CMV infection in premature infants, suggesting that these infants do not develop cognitive function delays or hearing loss, although those with intrapartum infection do. Readily available methods of treating breast milk to inactivate the CMV either diminish the immunologic and nutritive benefits of breast milk or incompletely inactivate the virus. This review considers the data on measuring CMV in breast milk, the recent clinical studies on CMV transmission via breast milk, reported methods of inactivation of CMV in breast milk, and immunologic factors that may play a role in transmission. CMV-IVIG treatment needs further evaluation but appears promising. Recommendations are made to help address the issue of CMV transmission to premature infants in clinical practice in the neonatal intensive care unit (NICU).

Breast milk and cytomegalovirus infection in preterm infants

The incidence of postnatal human cytomegalovirus (HCMV) reactivation during lactation equals the maternal seroprevalence. Infectious virus, viral DNA and RNA can be isolated from cells and fat free milk whey. Early onset of viral DNAlactia and virolactia as well as high viral load in milk whey are maternal risk factors for virus transmission. Preterm infants below 1000 g birthweight and a gestational age below 30 weeks may be at high risk of acquiring a symptomatic HCMV infection. Several recent studies using frozen milk for feeding describe low transmission rates and mostly asymptomatically infected neonates. However despite different freeze-storing procedures HCMV transmission occurred and severe HCMV infections were observed. Only few data exist on the long-term outcome of postnatally acquired HCMV infection via breast milk. Additional long-term outcome studies are needed. The newly developed short-term pasteurisation may be a reliable alternative to freezing and Holder pasteurisation, since important milk constituents are conserved.

Cytomegalovirus

PURPOSE OF REVIEW

To identify recent developments in the management of congenital cytomegalovirus infection which continues to exact a heavy toll on the developing central nervous system.

RECENT FINDINGS

A major advance is the publication of a randomized controlled trial showing that hearing loss is significantly decreased by ganciclovir. This treatment should now be offered to all neonates who would have met the eligibility criteria of the trial, that is proven congenital infection with central nervous system involvement when treatment is begun within 1 month of birth. A second major advance is the use of stored dried blood spots to detect cytomegalovirus DNA and so differentiate congenital infection from perinatal infection. This approach has the potential to diagnose a proportion of cases of hearing loss and mental retardation which are currently labelled idiopathic. A third major advance is the clinical evaluation of vaccines against cytomegalovirus. Experiments with guinea pig cytomegalovirus show reduced fetal mortality and congenital infection among dams given vaccines containing the glycoprotein B of the virus. A different vaccine glycoprotein B construct has been shown to be immunogenic and well tolerated in healthy adult and paediatric humans. Recent reviews from the Institute of Medicine and the National Vaccine Advisory Committee emphasize the financial and humanitarian justifications for developing cytomegalovirus vaccines as a high priority.

SUMMARY

Substantial progress has recently been made in diagnosis and treatment. If additional financial support were to be made available to evaluate existing vaccine candidates in controlled clinical trials, congenital cytomegalovirus could potentially become a vaccine-preventable disease.