Prospective identification of congenital cytomegalovirus infection in newborns using real-time polymerase chain reaction assays in dried blood spots

Ophthalmic Complications, Diagnosis, and Treatment of Congenital Human Cytomegalovirus Infection

Background: Human cytomegalovirus (hCMV) is the most common etiological agent of congenital infections seen in newborns. Among the most commonly observed complications in children with congenital human cytomegalovirus infection are those affecting the visual system. Ocular complications of congenital CMV (cCMV) are a topic rarely addressed in the literature, which prompted the authors to update the available knowledge with the latest data. Methodology: English-language literature published between April 2000 and November 2023 (PubMed, NIH, Google Scholar) was analyzed for ocular complications of cCMV. The data obtained were categorized according to the ocular area involved and the incidence. A compilation of criteria for the symptomatic form of cCMV was also created. Results: The cCMV complications described in the literature affect all parts of the visual system: the anterior segment, the posterior segment, the posterior visual pathways, and the visual cortex. The most commonly described ocular complication of cCMV is choroidal and retinal scarring. Conclusions: Ophthalmic complications of cCMV can cause severe visual disturbances. Ophthalmic diagnosis in newborns should include hCMV PCR testing, which has the highest sensitivity and specificity. In the symptomatic form of cCMV, treatment should be instituted according to recommendations. A consensus should be established for screening of primary hCMV infection in pregnant women, the way in which to define the symptomatic form of cCMV, and the appropriateness and standards of treatment for primary hCMV infection in pregnant women.

Implementation of pooled saliva tests for universal screening of cCMV infection

Congenital cytomegalovirus (cCMV) is the most common intrauterine infection, leading to neurodevelopmental disabilities. Universal newborn infant screening of cCMV has been increasingly advocated. In the absence of a high-throughput screening test, which can identify all infected newborn infants, the development of an accurate and efficient testing strategy has remained an ongoing challenge. Here we assessed the implementation of pooled saliva polymerase chain reaction (PCR) tests for universal screening of cCMV, in two hospitals of Jerusalem from April 2022 through April 2023. During the 13-month study period, 15,805 infants (93.6% of all live newborn infants) were screened for cCMV using the pooled approach that has since become our routine screening method. The empirical efficiency of the pooling was six (number of tested newborn infants per test), thereby sparing 83% of the saliva tests. Only a minor 3.05 PCR cycle loss of sensitivity was observed for the pooled testing, in accordance with the theoretical prediction for an eight-sample pool. cCMV was identified in 54 newborn infants, with a birth prevalence of 3.4 per 1,000; 55.6% of infants identified with cCMV were asymptomatic at birth and would not have been otherwise targeted for screening. The study demonstrates the wide feasibility and benefits of pooled saliva testing as an efficient, cost-sparing and sensitive approach for universal screening of cCMV.

Loop-mediated isothermal amplification assay for screening congenital cytomegalovirus infection in newborns

Congenital cytomegalovirus (CMV) infection is a common cause of sensorineural hearing loss and neurodevelopmental impairment in newborns. However, congenital CMV infection cannot be diagnosed using samples collected more than 3 weeks after birth because testing after this time cannot distinguish between congenital infection and postnatal infection. Herein, we developed a robust loop-mediated isothermal amplification (LAMP) assay for the large-scale screening of newborns for congenital CMV infection. In contrast to conventional quantitative polymerase chain reaction (qPCR), which detects CMV within a dynamic range of 1.0 × 106 to 1.0 × 102 copies/μL, our quantitative LAMP assay (qLAMP) detects CMV within a dynamic range of 1.1 × 108 to 1.1 × 103 copies/μL. Moreover, the turnaround time for obtaining results following DNA extraction is 90 min in qPCR but only 15 min in qLamp. The colorimetric LAMP assay can also detect CMV down to 1.1 × 103 copies/μL within 30 min, irrespective of the type of heat source. Our LAMP assay can be utilized in central laboratories as an alternative to conventional qPCR for quantitative CMV detection, or for point-of-care testing in low-resource environments, such as developing countries, via colorimetric naked-eye detection. KEY POINTS: • LAMP assay enables large-scale screening of newborns for congenital CMV infection. • LAMP allows colorimetric or quantitative detection of congenital CMV infection. • LAMP assay can be used as a point-of-care testing tool in low-resource environments.

Utility of Dried Blood Spots for the Diagnosis of Congenital Cytomegaloviruses within the First 21 Days of Life in a Single Center

In this retrospective study, we aimed to evaluate the performance of dried-blood-spot (DBS) testing as a diagnostic method for the congenital cytomegalovirus (cCMV). We reviewed the medical records and DBS test results of 89 patients who had also undergone diagnostic cCMV testing within the first 21 days of life. The DBS test had a sensitivity of 83.9%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 73%. Patients with a true-positive DBS had a higher median level of CMV in blood according to PCR than those with a false-negative result. Additionally, all patients with cCMV and hearing loss had a positive DBS test, with higher median viremia levels observed in those with hearing loss compared to those without a CMV PCR blood test. These results suggest that DBS-based testing is useful in the diagnosis of cCMV, and its performance may be related to levels of CMV viremia. DBS testing accurately identified those patients with congenital/early onset hearing loss and those at risk of developing late-onset hearing loss.

Congenital CMV associated with diaphragm dysfunction: a rare cause of tachypnoea

A late preterm infant with intrauterine growth restriction developed respiratory distress, tachypnoea and hypoxia after birth, requiring supplemental oxygen. Chest radiographs demonstrated persistent elevation of the right hemidiaphragm. Chest ultrasound initially demonstrated symmetrical bilateral diaphragm motion, but subsequent ultrasounds showed asymmetrical excursion with weaker movement of the right hemidiaphragm. Placental pathology demonstrated chronic infectious villitis secondary to cytomegalovirus (CMV), and subsequent CMV testing on the infant was positive. The infant was microcephalic and head imaging revealed intracranial calcifications, consistent with congenital CMV infection.CMV is the most common congenital infection and has a wide array of clinical manifestations. This report highlights the rarely described association between congenital CMV infection and respiratory distress due to underlying diaphragm dysfunction. In neonates with respiratory distress and features of congenital CMV infection, clinicians should have a high index of suspicion for diaphragm dysfunction.

Early Identification and Management of Congenital Cytomegalovirus

Congenital cytomegalovirus (cCMV) is the most common nongenetic cause of sensorineural hearing loss. Despite its prevalence, universal screening for cCMV is not currently performed. Hearing loss caused by cCMV is most often severe to profound, often bilateral, and may be fluctuating or progressive. Infants with hearing loss at birth and confirmed cCMV might benefit from antiviral therapy. Roughly half of hearing loss cases owing to cCMV are delayed in onset, and consequently, these children pass newborn hearing screening. Children with cCMV require close audiologic monitoring, require appropriate management with hearing aids, and should be monitored for cochlear implant candidacy.

Congenital Cytomegalovirus Infection: Epidemiology, Timely Diagnosis, and Management

Congenital cytomegalovirus (cCMV) infection is common because of the ubiquitous nature of the virus and the lack of an effective prevention strategy during pregnancy. Most infants with cCMV are asymptomatic, although a notable subset can have sequelae including, most commonly, sensorineural hearing loss and neurodevelopmental disability, which may not be present at birth. Timely screening for cytomegalovirus in the first weeks after birth is critical to appropriately diagnose congenital infection, evaluate affected infants, and determine the treatment course. Antiviral therapy with valganciclovir can optimize end hearing and neurodevelopmental outcomes in symptomatic infants. This review discusses the epidemiology and clinical manifestations of cCMV, targeted and universal screening approaches, and treatment and monitoring of infants with cCMV.

Clinical outcome and the role of antivirals in congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection is a leading cause of hearing loss and neurological disabilities in children worldwide. Although a minority of infants with cCMV will have symptoms at a birth, these children are at high risk of long-term sequelae. Most infants with cCMV have no clinical signs at birth (asymptomatic), but 10-15% will develop hearing loss. The diagnosis of cCMV relies on detection of the virus from urine or saliva within the first three weeks of life, with saliva PCR being the preferred method due to ease of collection and high sensitivity of the assay. Measures to prevent mother-to-child transmission of CMV are limited, and antiviral therapy with valganciclovir for 6 months is the standard of care for infants with symptomatic cCMV. As more infants with cCMV are being identified through newborn screening, studies are urgently needed to address antiviral treatment in asymptomatic infants and the implementation of prevention strategies to prevent fetal infection. This article is part of the symposium "New drugs and vaccines for DNA virus infections: a symposium in memory of Mark Prichard."

Congenital Cytomegalovirus Infection

Congenital cytomegalovirus (cCMV) infection is a leading cause of hearing loss and neurological disabilities in children, with the disease burden and disabilities due to cCMV greater than many other well recognized childhood conditions. A minority of infants with cCMV will have symptoms at birth. Infants with symptomatic cCMV are at higher risk for sequelae than those born without symptoms. The majority of infants with cCMV are asymptomatic at birth, but 10%-15% will develop hearing loss. Although clinical symptoms can help predict which infants will have sensorineural hearing loss, among asymptomatic cCMV there are currently no predictors of adverse outcome. The identification of a biomarker to identify those at highest risk of sequelae is highly desirable to target interventions to those who could potentially benefit. Because there is increasing rationale for establishing both targeted and universal screening programs for cCMV in the United States and worldwide, this is an urgent priority.

Cytomegalovirus infection during pregnancy: state of the science

Cytomegalovirus is the most common congenital infection, affecting 0.5-2% of all live births and the main nongenetic cause of congenital sensorineural hearing loss and neurological damage. Congenital cytomegalovirus can follow maternal primary infection or nonprimary infection. Sensorineurological morbidity is confined to the first trimester with up to 40-50% of infected neonates developing sequelae after first-trimester primary infection. Serological testing before 14 weeks is critical to identify primary infection within 3 months around conception but is not informative in women already immune before pregnancy. In Europe and the United States, primary infection in the first trimester are mainly seen in young parous women with a previous child younger than 3 years. Congenital cytomegalovirus should be evoked on prenatal ultrasound when the fetus is small for gestation and shows echogenic bowel, effusions, or any cerebral anomaly. Although the sensitivity of routine ultrasound in predicting neonatal symptoms is around 25%, serial targeted ultrasound and magnetic resonance imaging of known infected fetuses show greater than 95% sensitivity for brain anomalies. Fetal diagnosis is done by amniocentesis from 17 weeks. Prevention consists of both parents avoiding contact with body fluids from infected individuals, especially toddlers, from before conception until 14 weeks. Candidate vaccines failed to provide more than 75% protection for >2 years in preventing cytomegalovirus infection. Medical therapies such as cytomegalovirus hyperimmune globulins aim to reduce the risk of vertical transmission but 2 randomized controlled trials have not found any benefit. Valaciclovir given from the diagnosis of primary infection up to amniocentesis decreased vertical transmission rates from 29.8% to 11.1% in the treatment group in a randomized controlled trial of 90 pregnant women. In a phase II open-label trial, oral valaciclovir (8 g/d) given to pregnant women with a mildly symptomatic fetus was associated with a higher chance of delivering an asymptomatic neonate (82%), compared with an untreated historical cohort (43%). Valganciclovir given to symptomatic neonates is likely to improve hearing and neurological symptoms, the extent of which and the duration of treatment are still debated. In conclusion, congenital cytomegalovirus infection is a public health challenge. In view of recent knowledge on diagnosis and pre- and postnatal management, health care providers should reevaluate screening programs in early pregnancy and at birth.

Saliva Real-Time Polymerase Chain Reaction for Targeted Screening of Congenital Cytomegalovirus Infection

BACKGROUND

Saliva real-time polymerase chain reaction (PCR) was shown to be sensitive and specific for the detection of congenital cytomegalovirus (cCMV) in universal screening studies. In the current study, we assessed the performance of saliva real-time PCR in newborns undergoing targeted cCMV screening.

METHODS

Saliva real-time PCR results were prospectively correlated with reference-standard urine detection in newborns undergoing targeted cCMV screening over a 3-year period, in successive validation (concurrent testing of all saliva and urine specimens) and routine-screening (confirmatory urine testing of positive saliva results) implementation phases.

RESULTS

The sensitivity, specificity, and positive and negative predictive values of saliva real-time PCR were 98.3% (95% confidence interval, 90.8%-99.9%), 91.5% (89.3%-93.3%), 45.6% (36.7%-54.7%), and 99.9% (99.2%-99.9%), respectively, in 856 concurrently tested newborns. True-positive saliva real-time PCR detection (defined in relation to urine detection) was associated with earlier saliva sampling (P = .002) and a higher saliva viral load (P < .001). We further identified a saliva viral load cutoff value that reliably distinguished between true-positive and false-positive saliva results.

CONCLUSIONS

In newborns undergoing targeted screening for cCMV, saliva real-time PCR is highly sensitive yet has a low positive predictive value, necessitating confirmatory testing. Early sampling and application of a validated viral load cutoff could improve the assay performance and support its large-scale implementation in this growing clinical setting.

Outcome and management of newborns with congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) infection is the most common non-genetic cause of hearing loss and neurological disorder in children. Its overall prevalence is approximately 0.5% in Europe. In France, systematic screening during pregnancy is not recommended; screening is performed only if there are maternal or fetal symptoms suggestive of this infection. Approximately 90% of infected newborns are asymptomatic at birth, and among them the risk of neurosensory sequelae is 5-15%. By contrast, the prevalence of neurosensory impairment in symptomatic newborns at birth varies from 17% to 60%. Congenital CMV infection must be confirmed at birth before the 21st day of life by polymerase chain reaction (PCR) on saliva or urine samples. A complete clinical examination, blood tests (blood count, liver function test, CMV PCR), hearing tests, brain ultrasound and eye fundus examination should be performed. Neurological and auditory follow-up must be extended well beyond the neonatal period because the occurrence of neurosensory sequelae may be delayed. Oral valganciclovir is the recommended treatment in moderate or severe congenital CMV infections for a period of 6 weeks to 6 months; such treatment requires regular monitoring because of its possible side effects.

[Neurological sequelae in patients with congenital cytomegalovirus]

INTRODUCTION

The infection due to cytomegalovirus is the most common congenital infection in developed countries, and on of the main causes of psychomotor impairment and neurosensory hearing loss of infectious origin. The present study has its objectives to describe the clinical-analytical and neuroimaging of patients with secondary neurological sequelae secondary to the congenital cytomegalovirus infection and then compare them with the group of patients with a congenital cytomegalovirus infection that did not have neurological symptoms during their follow-up.

MATERIAL AND METHODS

A retrospective, observational, cohort study was conducted that included all the cases of congenital cytomegalovirus infection from 2003 until 2018 and the short-medium term neurological sequelae were evaluated. Prenatal, perinatal, and postnatal data of patients with neurological sequelae were compared against those that did not present with any.

RESULTS

A total of 60 patients with congenital cytomegalovirus infection were recorded during the study period, with 65% having neurological involvement during their follow-up period (62.2% with psychomotor impairment, 61.5% with microcephaly, 46.2% loss of hearing, 27.8% motor disorders, 20.5% epilepsy, and 5.6% with chorioretinitis). In the patient group that had sequelae, the presence of clinical symptoms during the neonatal period, as well as changes in the neuroimaging study, were the most common, with both being statistically significant compared to the asymptomatic group. The patients with neurological involvement also had a higher score on the Noyola et al. neuroimaging scale.

CONCLUSIONS

The symptoms at birth, and certain findings in the neuroimaging, like the changes in the white matter or neuronal migration disorders, could predict neurocognitive sequelae in patients with congenital cytomegalovirus infection.

Blood viral load in the diagnostic workup of congenital cytomegalovirus infection

BACKGROUND

There is limited data on the role of cytomegalovirus (CMV) blood quantitative polymerase chain reaction (qPCR) in the diagnostic workup of congenital CMV (cCMV) infection.

OBJECTIVES

The objective of this study was to determine if CMV blood qPCR at the time diagnosis could differentiate between symptomatic and asymptomatic infants according to the recent consensus classification.

STUDY DESIGN

Retrospective study of children diagnosed with cCMV infection at CHU Sainte-Justine, Montreal, Canada, between 2008 and 2016. Cases for whom qPCR was done at baseline (<4 weeks of age) alongside a complete diagnostic workup were included. The association between CMV blood viral load (VL) and clinical severity group was determined. The probability of having moderate to severe symptoms was assessed using univariate logistic regression analysis.

RESULTS

Forty-seven patients were included in the analysis. Median VL was significantly higher among infants with moderate to severely symptomatic disease vs. those asymptomatic or asymptomatic with isolated sensorineural hearing loss (SNHL) (13 736 vs. 1876 copies/ml, p = 0.004), infants with moderate to severe disease or asymptomatic with isolated SNHL vs. asymptomatic (17 736 vs. 1496 copies/ml, p < 0.001), and in infants with baseline neurological involvement vs. those without (17 317 vs. 2641 copies/ml, p = 0.03). Using logistic regression, an infant would have a >75 % probability of being moderate to severely symptomatic above 18 770 copies/ml, with a threshold of 100 000 copies/ml approaching a 100 % probability.

CONCLUSIONS

Our baseline assessment of CMV blood VL suggests that that the level of CMV viremia correlates with symptom severity.

Congenital Cytomegalovirus Infection in Children with Autism Spectrum Disorder: Systematic Review and Meta-Analysis

Association of congenital cytomegalovirus (CMV) infection with autism spectral disorder (ASD) has been suggested since 1980s. Despite the observed association, its role as a risk factor for ASD remains to be defined. In the present review, we systematically evaluated the available evidence associating congenital CMV infection with ASD using PubMed, Web of Science, Cochrane Library, and Embase databases. Any studies on children with CMV infection and ASD were evaluated for eligibility and three observational studies were included in meta-analysis. Although a high prevalence of congenital CMV infection in ASD cases (OR 11.31, 95% CI 3.07-41.66) was indicated, too few events (0-2 events) in all included studies imposed serious limitations. There is urgent need for further studies to clarify this issue.

Is Polymerase Chain Reaction in Neonatal Dried Blood Spots Reliable for the Diagnosis of Congenital Cytomegalovirus Infection?

BACKGROUND

Detection of cytomegalovirus (CMV) DNA by real-time polymerase chain reaction (rt-PCR) in dried blood spots (DBSs) collected for newborn screening has been assessed for retrospective diagnosis of congenital CMV (cCMV) infection, with variable results (sensitivities ranging from 34% to 100%). We aimed to assess the accuracy of this technique in Spain in a large patient series.

METHODS

Ambispective, multicenter study including patients with confirmed cCMV from the Spanish Registry of cCMV patients. cCMV was established on the presence of CMV DNA in any body fluid, by positive culture findings or by molecular techniques during the first 2 weeks of life. Children in whom cCMV had been excluded were used as negative controls. Neonatal DBS samples were collected from both groups. The presence of CMV DNA was assessed by rt-PCR (RealStar CMV, Altona, Germany) in a central laboratory.

RESULTS

One-hundred three patients and 81 controls from 10 hospitals were included. The performance of CMV DNA determination in DBS for the diagnosis of cCMV was as follows (95% confidence interval): sensitivity 0.56 (0.47-0.65), specificity 0.98 (0.91-0.99), positive likelihood ratio 22.81 (5.74-90.58) and negative likelihood ratio 0.45 (0.36-0.56). Sensitivity increased with the birth viral load (bVL) log category. In cCMV patients, lower bVL was the single variable associated with a negative DBS rt-PCR result (P = 0.017).

CONCLUSIONS

The sensitivity of CMV rt-PCR in DBS in our series was low and correlated with the bVL. Thus, a negative DBS result would not rule out cCMV infection, especially in patients with a low viremia level at birth.

Unilateral congenital hearing loss in children: Challenges and potentials

The estimated incidence of sensorineural hearing impairment (>40 dB HL) at birth is 1.86 per 1000 newborns in developed countries and 30-40% of these are unilateral. Profound sensorineural unilateral hearing impairment or single sided deafness (SSD) can be treated with a cochlear implant. However, this treatment is costly and invasive and unnecessary in the eyes of many. Very young children with SSD often do not exhibit language and cognitive delays and it is hard to imagine that neurocognitive skills will present difficulties with one good ear. In the current paper we review the most recent evidence on the consequences of unilateral hearing impairment for auditory and neurocognitive factors. While data of both adults and children are discussed, we focus on developmental factors, congenital deafness and a window of opportunity for intervention. We discuss which etiologies qualify for a cochlear implant and present our multi-center prospective study on cochlear implants in infants with one deaf ear. The large, state-of-the art body of research allows for evidence-based decisions regarding management of unilateral hearing loss in children.

Evaluation of rapid and sensitive DNA extraction methods for detection of cytomegalovirus in dried blood spots

BACKGROUND

Dried blood spots (DBS), collected universally from newborns in the U.S., could be used as a matrix for the detection of cytomegalovirus (CMV) infection in infants. However, sensitivity to detect CMV in DBS as compared to saliva and urine is variable across studies largely due to the DNA extraction method. Thermal shock, a widely used DNA extraction method, is highly sensitive for the detection of CMV in DBS, however, the processing time required is not practical for high-throughput testing.

OBJECTIVE

To determine if rapid and cost-effective DNA extraction methods amenable to newborn screening (NBS) could achieve the same sensitivity as the thermal shock method.

STUDY DESIGN

DBS were prepared from CMV positive blood samples from 20 organ transplant recipients. Three DNA extraction methods were compared for relative yield and sensitivity of detection of CMV DNA: thermal shock, KOH Tris buffer, and DNA Extract All. CMV DNA was detected by real-time quantitative polymerase chain reaction (qPCR).

RESULTS

The KOH Tris and DNA Extract All methods gave higher yields and sensitivity of CMV detection in DBS than thermal shock, which were significantly greater when viral loads were ≤ 10,000 copies/ml blood. Both methods gave faster turnaround times than thermal shock and would be better suited for NBS.

CONCLUSIONS

The choice of DNA extraction method greatly influences the ability to detect low levels of CMV DNA in DBS. Moreover, development of highly sensitive yet rapid methods for CMV detection could help facilitate future newborn screening of CMV in DBS.

Viral Loads in Congenital Cytomegalovirus Infection From a Highly Immune Population

Among newborns with congenital cytomegalovirus (CMV) infection from China, there was no difference in CMV viral load in saliva specimens dried and stored at room temperature compared with those kept wet and stored cold, even after longer storage time for the former than the later (74 vs 58 days, P = .02).

Detection of congenital cytomegalovirus in newborns using nucleic acid amplification techniques and its public health implications

Human cytomegalovirus (HCMV), a herpesvirus, is an important human pathogen that causes asymptomatic infections in healthy or immunocompetent individuals but can lead to severe and potentially life-threatening complications in immune-immature individuals such as neonates or immune-compromised patients such as organ-transplant recipients and HIV-positive individuals. Congenital HCMV infection represents a significant public health issue and poses substantial healthcare and economic burden to society. This virus causes the most common viral congenital infection worldwide, and is the leading non-genetic cause of sensorineural hearing loss in children in developed countries. Congenital HCMV infection is believed to fulfill the criteria of the American College of Medical Genetics to be considered as a condition targeted for a newborn screening program. This is because congenital HCMV infection can be identified during a time (within 2 days after birth) at which it would not ordinarily be detected clinically, and there are demonstrated benefits of early detection, timely intervention, and efficacious treatment of the condition. Recent progresses in developing polymerase chain reaction-based approaches to detect HCMV in samples obtained from newborns have generated much excitement in the field. In this review, we highlight the recent progress in diagnostic techniques that could potentially be used for the detection of HCMV infection in neonates and its direct implications in public health settings for diagnosing congenital HCMV infection.

Unilateral Sensorineural Hearing Loss: Medical Context and Etiology

Objective: Unilateral sensorineural hearing loss (USNHL) is known to impact on school performance and social skills during childhood, but the etiologies remain unclear. The aim of this study was to assess various etiologies and to study the clinical contexts in this population. Methods: The study is a retrospective review. Characteristics of hearing loss (HL), audiometric parameters, imaging, and genetic and medical contexts were analyzed. Results: Eighty children were included. USNHL was profound in 68%, could be progressive in 19%, and become bilateral in 7.5% of cases. Inner ear malformations were identified in 41% of cases; cochlear nerve deficiency (CND) was frequent (33%). Cytomegalovirus (CMV) infection and genetic syndromes were confirmed in 10 and 6% of cases, respectively. Conclusion: Long-term hearing follow-up remains useful in USNHL as it can become bilateral. Looking to etiology, MRI should be the gold standard, as CND is frequently observed and screening for CMV infection should be systematic. Genetic etiologies appear to be different compared to bilateral HL. Further genetic research in this domain is needed.

Congenital Cytomegalovirus infection: advances and challenges in diagnosis, prevention and treatment

Cytomegalovirus (CMV) is the most frequent cause of congenital infection worldwide, with an estimated incidence in developing countries of 0.6-0.7% of all live births. The burden of disease related to congenital CMV in substantial, as it is the leading non-genetic cause of sensorineural hearing loss and an important cause of neurodevelopmental disabilities in children. Despite its clinical significance, congenital CMV infection often goes undetected because the majority of infected infants are asymptomatic at birth and screening programs have not been substantially implemented. Other than behavioral measures, effective interventions aimed at the prevention of maternal infection and of mother-to-child transmission are lacking. Due to a convergence of recent advances in both diagnostic and therapeutic strategies in infants with congenital CMV, though, the field likely will be changing rapidly over just the next few years. Specifically, a highly-sensitive screening test with high throughput potential has been developed, and treatment of infants symptomatically infected with congenital CMV has proven to be well-tolerated and effective in improving long-term hearing and neurodevelopmental outcomes.This review highlights the clinical importance of congenital CMV infection, the developments in laboratory diagnostics, and the benefits of antiviral therapy. It also identifies the global efforts still required in the prevention of maternal infection and in the optimization of antiviral therapy to further reduce the burden of congenital CMV disease.

Cohort study on maternal cytomegalovirus seroprevalence and prevalence and clinical manifestations of congenital infection in China

Congenital cytomegalovirus (CMV) infection is the leading viral cause of birth defects and developmental disabilities in developed countries. However, CMV seroprevalence and burden of congenital CMV infection are not well defined in China.Cohort of newborns from 5 birthing hospitals in 2 counties of Shandong Province, China, were enrolled from March 2011 to August 2013. Dried blood spots (DBS) and saliva were collected within 4 days after birth for IgG testing for maternal seroprevalence and real-time PCR testing for congenital CMV infection, respectively.Among 5020 newborns tested for CMV IgG, 4827 were seropositive, resulting in CMV maternal seroprevalence of 96.2% (95% confidence interval [CI]:95.6%-96.7%). Of the 10,933 newborns screened for congenital CMV infection, 75 had CMV detected, resulting in an overall prevalence of 0.7% (95% CI: 0.5%-0.9%), with prevalences of 0.4% (14/3995), 0.6% (66/10,857), and 0.7% (52/7761) for DBS, wet saliva, and dried saliva specimens screened, respectively. Prevalence of congenital CMV infection decreased with increasing maternal age (0.9%, 0.6%, and 0.3% among newborns delivered from mothers aged 16-25, 26-35, and >35 years, respectively; P = 0.03), and was higher among preterm infants than full term infants (1.3% vs 0.6%, P = 0.04), infants with intrauterine growth restriction (IUGR) than those without (1.8% vs 0.7%, P = 0.03), and twins or triplets than singleton pregnancies (2.8% vs 0.7%, P = 0.04). None of the 75 newborns exhibited symptomatic congenital CMV infection, and there was no difference in clinical characteristics and newborn hearing screening results between infants with and without congenital CMV infection at birth.Congenital CMV infection prevalence was lower and the clinical manifestations were milder in this relatively developed region of China compared to populations from other countries with similarly high maternal seroprevalence. Follow-up on children with congenital CMV infection will clarify the burden of disabilities from congenital CMV infection in China.

Clinical Implications for Children Born With Congenital Cytomegalovirus Infection Following a Negative Amniocentesis

BACKGROUND

Recently, congenital cytomegalovirus (cCMV) infection was reported irrespective of a negative amniotic fluid prenatal analysis for cytomegalovirus (CMV). The question of whether this phenomenon represents low sensitivity of the test or late development of fetal infection (after amniocentesis) was discussed, but not answered. However, if late transmission is the rule, then infants born with cCMV after negative amniocentesis would be expected to carry better prognosis than those who tested positive.

METHODS

Data of all infants with cCMV infection, followed in 2 pediatric centers from 2006 to 2015, were reviewed. Infant outcome after birth of symptomatic vs asymptomatic disease was compared with infants born after a negative amniocentesis (study group) and those with a positive amniocentesis (control group).

RESULTS

Amniocentesis was performed in 301 pregnancies of our cohort of infants with cCMV and was negative for CMV in 47 (15.6%). There were fewer symptomatic cCMV neonates in the study group than in the control group (4.3% vs 25%; P < .001). Hearing impairment at birth was also less frequent in the study group (2.2% vs 17.4%; P = .012). None of the children in the study group had neurologic sequelae at long-term follow up, compared with 13 (14.1%) in the control group (P < .001).

CONCLUSIONS

Although negative amniocentesis does not exclude cCMV, infants with cCMV born after a negative amniocentesis seldom present with mild clinical symptoms or cerebral ultrasound features at birth. These children also have a very good long-term outcome. Our findings support the theory of a late development of fetal infection, after the time of the amniocentesis.

Gold magnetic nanoparticle conjugate-based lateral flow assay for the detection of IgM class antibodies related to TORCH infections

In this study, a lateral flow immunochromatographic assay (LFIA) system for the detection of immunoglobulin M (IgM) antibodies, related to TORCH [(T)oxoplasmosis, (O)ther agents, (R)ubella (also known as German Measles), (C)ytomegalovirus, and (H)erpes simplex virus infections], based on gold magnetic nanoparticles, was established. Following modification with poly(methacrylic acid), the gold magnetic nanoparticles conjugated with an anti‑human IgM antibody (μ‑chain specific) to construct a probe. A lateral flow assay device was constructed based on these conjugates. IgM antibodies to four types of pathogens, notably toxoplasmosis, rubella virus, cytomegalovirus and herpes simplex virus type 2, were detected using this device. Compared with commercial colloidal gold‑based LFIA strips, our method exhibited higher sensitivity. No interference with triglycerides, hemoglobin and bilirubin occurred, and no cross‑reactivity was noted among the four pathogens. The gold magnetic nanoparticle‑LFIA strips were used to assess 41 seropositive and 121 seronegative serum samples. The sensitivity was 100% (162/162) and the specificity was 100% (162/162). This method cannot only be used for the detection of TORCH IgM-specific antibodies, but it can potentially be developed for use in the diagnosis of other acute or recently identified autoimmune diseases.

Evaluation of 98 immunocompetent children with cytomegalovirus infection: importance of neurodevelopmental follow-up

This study aims to analyze and evaluate the clinic and demographic features of immunocompetent children that have been diagnosed with cytomegalovirus (CMV) infection. The data of children diagnosed with CMV infection between January 2005 and December 2010 and their follow-ups for 2 years were retrospectively evaluated. Ninety-eight patients were included, and the median age at admission was 5.6 months (5 days-36 months). 54.1% was male. The diagnosis of CMV infection was performed by measurement of serum anti-CMV specific Ig M and IgG titers and PCR method in blood and/or urine. In 3.06% of the patients, congenital infection was detected, whereas possible congenital infection was observed in 36.7% of the patients. Furthermore, 44 patients (44.8%) were detected to have perinatal infection while postnatal infection was spotted in 15.3% of the patients. The common presenting manifestations were prolonged jaundice, diarrhea, vomiting, abdominal distension, skin eruption, and seizure. And the most common physical examination findings were hepatosplenomegaly, microcephaly, jaundice, and petechia. The mainstream laboratory results were elevated transaminases (50%), anemia (30.6%), leukocytosis (27.5%), and thrombocytopenia (18.3%). There were intracranial calcification in 5.1% and eye findings in 5.1%. On follow-up of patients, complete improvement (59.1%), neuromotor developmental delay (11.2%), epilepsy (10.2%), hearing loss (3.06 %), hemolytic anemia (2.04%), and growth retardation (1.02%) were detected.

CONCLUSION

CMV infection is a significant disease both in congenital and perinatal period. It must be considered that diagnosed patients need to be monitored for a long time with special attention to their neurodevelopmental follow-ups.

Incidence of CMV co-infection in HIV-positive women and their neonates in a tertiary referral centre: a cohort study

Co-infection with CMV in HIV-positive pregnant women is associated with perinatal mother-to-child transmission (MTCT) of both viruses. This retrospective study reports on the incidence of maternal and neonatal CMV (presence of anti-CMV IgG and IgM, CMV DNA PCR and/or CMV virus isolation) in high-risk pregnancies due to maternal HIV infection, MTCT of HIV and/or CMV. One hundred and eleven maternal samples and 75 matched neonatal samples were available for HIV and subsequent CMV testing. In this cohort of HIV-positive pregnant women, 96 (86.5 %) serum samples were anti-CMV IgG positive. In nine (9.4 %) of these, anti-CMV IgM was detected, and in none of them a maternal primary CMV infection was suspected. Fifty-seven (51.8 %) maternal serum samples were tested retrospectively by CMV DNA PCR; one sample was positive (0.9 %). All matched neonates were tested for HIV by PCR in the first month of life; HIV transmission was detected in one case. In 74 (67.2 %) of neonates, CMV testing was performed. Sixty-six of these serum samples were tested retrospectively by CMV DNA PCR. Two newborns (2.7 %) showed laboratory markers for CMV infection (one by detection of CMV DNA in plasma, and one by isolation of CMV from a urine sample). In the follow-up, neither of these two showed clinical signs for active CMV disease. We discussed these findings in the light of the national official guidelines. All CMV transmissions occurred due to maternal reinfection or endogenous reactivation. This suggests the success of highly active antiretroviral therapy in preventing MTCT of HIV and CMV disease and highlights the importance of adequate care and follow-up.

Current controversies in diagnosis, management, and prevention of congenital cytomegalovirus: updates for the pediatric practitioner

Congenital cytomegalovirus (CMV) infection has been called "the elephant in our living room" because it is a major public health problem that for decades has been unrecognized and unaddressed. Congenital CMV infection is a common cause of sensorineural hearing loss, vision loss, neurodevelopment disabilities, liver disease, and growth failure. Diagnostic tests are now widely available to identify newborns with congenital CMV infection, congenitally infected newborns now can be easily assessed for evidence of organ involvement, and there are now antiviral treatments and other interventions available to improve the outcome in children with congenital CMV disease. A licensed vaccine to prevent CMV infection is not yet available; however, a "CMV knowledge vaccine," composed of "an ounce of CMV awareness and three simple precautions" and that is endorsed by the Centers for Disease Control and Prevention is available for pregnant women who wish to reduce their contact with potentially CMV-infected secretions and therefore reduce their risk of acquiring CMV during pregnancy. Medical experts in the field of congenital CMV have been called upon for a consensus statement for diagnosis and treatment, and nonprofit organizations of families affected by congenital CMV from around the world have formed a collaborative coalition to facilitate the spread of CMV knowledge and awareness.

Dried blood spots PCR assays to screen congenital cytomegalovirus infection: a meta-analysis

The performance of dried blood spots (DBS) polymerase chain reaction (PCR) assays in screening for congenital cytomegalovirus (cCMV) infection varies between different studies. To determine whether the DBS PCR assay has sufficient accuracy to be used as a screening test for cCMV infection, we performed a meta-analysis of 15 studies (n = 26007 neonates) that evaluated the performance of DBS PCR tests in screening for cCMV infection and that met our inclusion criteria. The pooled sensitivity and specificity were 0.844 (95% CI = 0.812–0.872) and 0.999 (95% CI = 0.998–0.999), respectively, and the diagnostic odds ratio was 1362.10 (95%CI = 566.91–3272.60). As sensitivity analysis showed that the results were robust. In conclusion, the performance of DBS PCR assays for testing cCMV was more suitable for retrospective diagnosis than screening.

Evaluation of DNA extraction methods for the detection of Cytomegalovirus in dried blood spots

BACKGROUND

Dried blood spots (DBS) are collected universally from newborns and may be valuable for the diagnosis of congenital Cytomegalovirus (CMV) infection. The reported analytical sensitivity for DBS testing compared to urine or saliva varies greatly across CMV studies. The purpose of this study was to directly compare the performance of various DNA extraction methods for identification of CMV in DBS including those used most often in CMV studies.

STUDY DESIGN

Whatman(®) Grade 903 filter paper cards were spotted with blood samples from 25 organ transplant recipients who had confirmed CMV viremia. Six DNA extraction methods were compared for relative yield of viral and cellular DNA: 2 manual solution-based methods (Gentra Puregene, thermal shock), 2 manual silica column-based methods (QIAamp DNA Mini, QIAamp DNA Investigator), and 2 automated methods (M48 MagAttract Mini, QIAcube Investigator). DBS extractions were performed in triplicate followed by real-time quantitative PCR (qPCR).

RESULTS

For extraction of both viral and cellular DNA, two methods (QIAamp DNA Investigator and thermal shock) consistently gave the highest yields, and two methods (M48 MagAttract Mini and QIAamp DNA Mini) consistently gave the lowest yields. There was an average 3-fold difference in DNA yield between the highest and lowest yield methods.

CONCLUSION

The choice of DNA extraction method is a major factor in the ability to detect low levels of CMV in DBS and can largely account for the wide range of DBS sensitivities reported in studies to date.

Genotype distribution, viral load and clinical characteristics of infants with postnatal or congenital cytomegalovirus infection

Background

Congenital cytomegalovirus infection is a leading cause of long-term sequelae. Cytomegalovirus is also frequently transmitted to preterm infants postnatally, but these infections are mostly asymptomatic. A correlation between cytomegalovirus genotypes and clinical manifestations has been reported previously in infants with congenital infection, but not in preterm infants with postnatal infection.

Objectives

The main objective of this study was to investigate cytomegalovirus genotype distribution in postnatal and congenital cytomegalovirus infection and its association with disease severity.

Methods

Infants admitted to the neonatal intensive care unit of the University Medical Center Utrecht, The Netherlands between 2003–2010 and diagnosed with postnatal or congenital cytomegalovirus infection were included. Classification of cytomegalovirus isolates in genotypes was performed upon amplification and sequencing of the cytomegalovirus UL55 (gB) and UL144 genes. Clinical data, cerebral abnormalities, neurodevelopmental outcome and viral load were studied in relation to genotype distribution.

Results

Genotyping results were obtained from 58 preterm infants with postnatal cytomegalovirus infection and 13 infants with congenital cytomegalovirus infection. Postnatal disease was mild in all preterm infants and all had favourable outcome. Infants with congenital infection were significantly more severely affected than infants with postnatal infection. Seventy-seven percent of these infants were symptomatic at birth, 2/13 died and 3/13 developed long-term sequelae (median follow-up 6 (range 2–8) years). The distribution of cytomegalovirus genotypes was comparable for postnatal and congenital infection. UL55 genotype 1 and UL144 genotype 3 were predominant genotypes in both groups.

Conclusions

Distribution of UL55 and UL144 genotypes was similar in asymptomatic postnatal and severe congenital CMV infection suggesting that other factors rather than cytomegalovirus UL55 and UL144 genotype are responsible for the development of severe disease.

[Can we rule out a congenital cytomegalovirus infection when the result of polymerase chain reaction in dried blood spots is negative?]

INTRODUCTION

The detection of cytomegalovirus (CMV) DNA by real time polymerase chain reaction (rt-PCR) in dried blood spots collected routinely for metabolic screening has been assessed for the retrospective diagnosis of congenital CMV (cCMV) infection in many studies, but not in Spain. The aim of this study is to analyze the diagnostic accuracy of this technique in our hospital.

METHODS

A cross-sectional retrospective observational study was conducted including all patients born between January, 2007 and September, 2012 with confirmed cCMV infection. The assessment of CMV DNA was made by using rt-PCR in dried blood spots of these patients.

RESULTS

Fourteen patients were included: 4/14 were symptomatic and 4/14 had sequelae. The detection of CMV DNA by rt-PCR was positive in only 7 patients. A statistically significant relationship between low viral load at birth and negative rt-PCR in dried blood spots was demonstrated.

CONCLUSIONS

Despite the low number of patients included, our data highlight an important amount of false negative results in the DNA CMV detection by rt-PCR in these samples for the retrospective diagnosis of cCMV infection, especially in cases with low viral load at birth.

Diagnosis of congenital cytomegalovirus infection in high risk neonates

Objectives

This study aimed to compare polymerase chain reaction (PCR) and IgM detection using enzyme linked immune-sorbent assay (ELISA) in diagnosis of congenital cytomegalovirus (CMV) infection.

Methods

This study was conducted from May 2009 to December 2010. Urine and blood samples were collected from 94 neonates with suspected congenital CMV infection. Serum and part of urine samples were stored at −20°C freezer, until the serologic and PCR tests were achieved. A 94 fresh urine samples were processed for cell culture. Nineteen (20.2%) out of 94 urine samples were proven positive for CMV infection by viral culture. For comparing PCR and IgM ELISA we used tissue culture technique as a reference, the 19 positive samples on culture (CMV group) and 20 negative samples (control group) were included in the comparison. Some characteristics of CMV and control groups were compared including sex, age, birth weight, gestational age < 37 and small for gestational age. Clinical and laboratory abnormalities were also compared in both groups.

Results

This study showed that the sensitivity and specificity of PCR in relation to viral culture were 100% and 100% respectively, there was excellent agreement between both tests (Kappa coefficient was 1 and P=0.000). On the other hand, the sensitivity of IgM CMV ELISA in relation to viral culture was 63.2% and the specificity was 85%. There was good agreement between both tests (Kappa coefficient was 0.48 and P=0.002). By comparing CMV and control groups, there were high statistically significant differences between both groups as regard the birth weight, gestational age < 37 and small for gestational age items (P= 0.00, 0.03 and 0.01 respectively). There were statistically insignificant differences as regarding the clinical and laboratory abnormalities detected for neonates of both groups. In this study jaundice (63%) and hepato-splenomegaly (42%) were the most common clinical signs in both groups.

Conclusions

PCR is more sensitive and specific technique for detection of congenital CMV infection than CMV IgM ELISA. Being more cost effective, less cumbersome and less time consuming in relation to viral culture, PCR may be used in detection of congenital CMV infection.

Management of pregnancies with confirmed cytomegalovirus fetal infection

Systematic screening for cytomegalovirus (CMV) maternal infection is not recommended in most countries. Nevertheless, primary CMV infection will occur in around 1% of women. The vertical transmission rate is estimated to be around 30-50%. Newborns with congenital CMV infection remain asymptomatic in the majority of cases and around 10% will present with a wide range of abnormalities. Fetal infection can be diagnosed by amniocentesis with amplification of the viral genome in the amniotic fluid by polymerase chain reaction. This prenatal diagnosis is mainly performed when ultrasound abnormalities are observed. The purpose of this mini-review is to describe the management options when a fetus is known to be infected.

Congenital cytomegalovirus is the second most frequent cause of bilateral hearing loss in young French children

OBJECTIVE

To estimate the prevalence of congenital cytomegalovirus (cCMV) among causes of bilateral hearing loss in young French children.

STUDY DESIGN

Children <3 years old with hearing loss were prospectively included at their first visit to a referral center. Cytomegalovirus polymerase chain reaction was performed on dried blood spots from Guthrie cards. Medical records were reviewed.

RESULTS

One hundred children with bilateral hearing loss were included at a median age of 15 months; the prevalence of cCMV was 8% (8/100) (95% CI, 2.7%-13.3%) in this population and 15.4% (8/52) in the subpopulation of children with profound bilateral hearing loss. Delayed neurodevelopment and brain abnormalities on computed tomography scan were found more often in children with cCMV than in children with hearing loss without cCMV (P = .027, P = .005). In 6 of 8 cCMV cases, cCMV infection had not been diagnosed before the study.

CONCLUSIONS

In a comprehensive study of the causes of bilateral hearing loss in young French children, cCMV is the second most frequent cause of hearing loss after connexin mutations. It underlines that a majority of French children with hearing loss and cCMV are not diagnosed early and therefore may not benefit from early intervention including the possibility of neonatal antiviral treatment. These results make the case for promoting systematic cytomegalovirus screening in neonates with confirmed hearing loss identified through neonatal hearing screening.

Standard reference material 2366 for measurement of human cytomegalovirus DNA

Human cytomegalovirus (CMV), classified as human herpesvirus 5, is ubiquitous in human populations. Infection generally causes little illness in healthy individuals, but can cause life-threatening disease in those who are immunocompromised or in newborns through complications arising from congenital CMV infection. An important aspect in diagnosis and treatment is to track circulating viral load with molecular methods, particularly with quantitative PCR. Standardization is vital, because of interlaboratory variability (due in part to the variety of assays and calibrants). Toward that end, the U.S. National Institute of Standards and Technology produced a Standard Reference Material 2366 appropriate for establishing metrological traceability of assay calibrants. This standard is composed of CMV DNA (Towne(Δ147) bacterial artificial chromosome DNA). Regions of the CMV DNA that are commonly used as targets for PCR assays were sequenced. Digital PCR was used to quantify the DNA, with concentration expressed as copies per microliter. The materials were tested for homogeneity and stability. An interlaboratory study was conducted by Quality Control for Molecular Diagnostics (Glasgow, UK), in which one component of SRM 2366 was included for analysis by participants in a CMV external quality assessment and proficiency testing program.

Maternal and neonatal anti-cytomegalovirus IgG level and risk of postnatal cytomegalovirus transmission in preterm infants

Immunological mechanisms influencing the risk of mother-to-child cytomegalovirus (CMV) transmission in preterm infants have not been studied sufficiently. In this study, the correlation between maternal and neonatal serum anti-CMV IgG levels and risk of postnatal CMV transmission in preterm infants was assessed. Anti-CMV IgG levels of 79 CMV seropositive mothers and their 94 infants were determined in peripheral blood samples collected within 3 days after delivery. Postnatal CMV infection was detected in 39/94 (41%) infants by PCR on urine at term-equivalent age (gestational age 40 weeks) after congenital infection was excluded. Maternal or infant anti-CMV IgG levels were not significantly different between infants with and without postnatal CMV infection. The anti-CMV IgG infant-mother ratio showed a significant positive correlation with gestational age (range 25-32 weeks, R(2)  = 0.218, P < 0.001), reaching 1.0 at 32 weeks of gestation. Anti-CMV IgG infant-mother ratio was significantly lower in infants with postnatal CMV infection (P = 0.015). In conclusion, the risk of postnatal CMV transmission is related to low gestational age and low anti-CMV IgG infant-mother ratio.

Congenital cytomegalovirus infection - a common cause of hearing loss of unknown aetiology

AIM

The aim of this study was to investigate the role of congenital cytomegalovirus (CMV) infection as a cause of various types of sensorineural hearing loss (SNHL) in a group of nonsyndromic children with otherwise unknown aetiology of hearing loss. Furthermore, the occurrence of combined congenital CMV infection and connexin 26 (Cx26) mutations was investigated.

METHODS

The dried blood spot (DBS) cards of 45 children with various degrees of hearing deficits and 46 children with severe/profound hearing loss were tested for CMV DNA with polymerase chain reaction (PCR) technique. The DBS cards of the 46 children with severe/profound hearing loss were also analysed for Cx26 mutations.

RESULTS

Of the 45 children with various degrees of hearing loss, nine were positive for CMV DNA (20%). The nine children represented severe/profound, mild and unilateral hearing loss. From the 46 children with severe/profound hearing loss, nine of 46 (20%) were positive for CMV DNA. In addition, three of the CMV DNA-positive children were carriers of mutations of Cx26.

CONCLUSION

Congenital CMV infection is a high risk factor in hearing impairment among children.

Infant death due to CMV enterocolitis

An infant was admitted with symptoms of diarrhoea and vomiting. After initial improvement she unexpectedly died. Postmortem confirmed a diagnosis of cytomegalovirus (CMV) enterocolitis. The authors report this case and review other published cases of immunocompetent infants who presented with this infection. Clinicians should consider stool CMV PCR test or referral for endoscopy and biopsy in young babies who present with profuse and prolonged episodes of diarrhoea. The value of ganciclovir in immunocompetent infants who suffer with CMV gastrointestinal involvement is still not clear.

Dried urine spots for detection and quantification of cytomegalovirus in newborns

Dried urine spots (DUS) have been reported to provide a simple screening tool for congenital cytomegalovirus (CMV) infection. We developed a standardized method for CMV quantification from DUS. Two applications of 20 μL urine remained within the rim of the filter paper disc and were used to determine the analytical performance of Towne CMV spiked into urine and applied on the discs. The measurable range spanned 3.7 to ≥8.0 log(10) copies/mL. The detection limit was 22 DNA copies/disc. Urine samples from congenitally infected newborns and negative controls were either diluted 1:10 or applied on filter paper at the same volume. DNA copy number from DUS correlated well with copy number from 1:10 diluted urine, although there was a trend for lower levels from DUS (0.3 log(10) difference). Our standardized method for CMV detection and quantification may facilitate CMV studies in resource-limited areas and allow for longitudinal monitoring of viral loads in treated infants.

Real-time PCR-based testing of saliva for cytomegalovirus at birth

Evaluation of: Boppana SB, Ross SA, Shimamura M et al. Saliva polymerase-chain-reaction assay for cytomegalovirus screening in newborns. N. Engl. J. Med. 364, 2111-2118 (2011). Cytomegalovirus (CMV) commonly causes congenital infection. As such, CMV is a prominent etiology for nongenetic sensori-neural hearing loss. However, screening examination in the perinatal and early infant period fails to identify most children at risk for CMV-produced hearing loss because of the absence of symptoms early in life. Furthermore, generalized screening for congenital CMV infection has yet to be implemented. Currently, newborns are tested via means of a rapid saliva culture but large-scale automation of this test would be difficult. Fortunately, newer potential replacement tests have been created. An important advance includes testing newborns via means of PCR using liquid or dried saliva samples. In a large-scale, prospective, multi-institutional study both types of salivary samples were compared with the gold standard of saliva culture. Of the 34,989 neonates tested, 0.5% or 177 samples tested positive for CMV. Testing of both liquid and dried saliva were sensitive (>97%) as well as specific (>98%) when measured against CMV culture. PCR testing of dried saliva has the potential benefit of adapting to generalized screening of neonates for congenital CMV infection. The advantages of early detection, intervention for and treatment of cases that are not clinically apparent needs to be carefully evaluated before proposing universal newborn screening for CMV infection as a valuable public health strategy.

Screening of congenital cytomegalovirus infection by real-time PCR in urine pools

Human cytomegalovirus (HCMV) is the most frequent cause of congenital infection. Despite the fact that 5-17% of asymptomatic infected babies will develop late sequelae and, therefore, should be closely followed, most of these children will remain undetected, as screening of all newborns by viral culture is too expensive and no valid alternative has been widely accepted. The aim of this work was to demonstrate that pool testing can be used to screen HCMV congenital infection in newborns. For this purpose, a real-time PCR technique was tested in urine pools. This pool method was applied to all urine specimens from children received in the virology laboratory of the Centro Hospitalar Cova da Beira for diagnosis of HCMV infection for a period of 14 months. Ten out of the 160 urine samples were tested positive by shell-vial culture and were also detected by this pool method. Additionally, 100 urine specimens, collected in 2004 and culture negative for HCMV were included to test the specificity of this methodology, all of which were negative. In conclusion, these results suggest that urine pools can be used to detect HCMV-positive urines in children, with similar sensitivity and specificity when compared with the standard method. Because of the very significant reduction both in terms of labour and cost of testing materials, this methodology may represent a valid option for screening the HCMV congenital infection in newborns.

Prevalence of congenital cytomegalovirus infection in Slovenia: a study on 2,841 newborns

Human cytomegalovirus (CMV) is the most frequent cause of congenital infection in humans. In the first prevalence study of congenital CMV infection in Eastern and Central Europe, all neonates born in a 22-month period in two Slovenian maternity units (total of 2,841 newborns) were screened prospectively for congenital CMV infection by a real-time polymerase chain reaction (PCR) in urine. In all newborns with positive screening results, plasma and dried blood spots (DBS) collected at birth were tested additionally for CMV DNA. Congenital CMV infection was confirmed by virus isolation from a urine sample collected within the first 2 weeks of life. Congenital CMV infection was identified in four out of 2,841 newborns tested (incidence 0.14%; 95% CI, 0.05-0.39%). In four newborns with confirmed congenital infection, the concentration of CMV DNA in urine ranged from 4.68 to 8.18 log(10)  copies/ml, all four newborns had detectable CMV DNA in plasma taken at birth (1.26-3.34 log(10)  copies/ml) and two out of four had detectable CMV DNA in DBS collected during newborn metabolic screening. None of the four newborns with confirmed congenital CMV infection was symptomatic. The study showed that the prevalence of congenital CMV infection at birth in Slovenia is among the lowest in the world and that CMV DNA PCR testing of urine is a suitable and affordable real-time screening strategy for congenital CMV infection. If it is performed in 24 mini-pools, the cost of screening is 1.4 €/newborn and the cost of detecting a single newborn with congenital CMV infection 1,000 €.