Neuroimaging in CMV congenital infected neonates: how and when

"Minimally symptomatic" congenital cytomegalovirus infection: latest data and emerging concepts

PURPOSE OF REVIEW

Universal and targeted screening of newborns for congenital cytomegalovirus (CMV) infection is increasing globally. Questions remain concerning the management of infants who have been identified with congenital CMV infection, especially those with "minimally symptomatic" or clinically inapparent infection. Our objective is to discuss current management of CMV-infected neonates with a focus on less affected infants with or without sensorineural hearing loss (SNHL).

RECENT FINDINGS

Valganciclovir is being prescribed increasingly in neonates with congenital CMV infection for improvement in hearing outcomes through 2 years of age. Treatment initiated in the first month of age is recommended for clinically apparent disease. A recent study showed hearing improvement at 18-22 months of age when therapy was initiated at age 1-3 months in infants with clinically inapparent CMV infection and isolated SNHL.

SUMMARY

Antiviral therapy with either ganciclovir or valganciclovir has shown moderate benefit in prevention of hearing deterioration among infants with clinically apparent CMV infection or isolated SNHL. Sustainability of benefit beyond 2 years of age remains unknown. At present, infants with clinically inapparent CMV infection (normal complete evaluation including hearing) should not receive antiviral therapy. All CMV-infected infants require close audiological and neurodevelopmental follow-up.

From Fetal to Neonatal Neuroimaging in TORCH Infections: A Pictorial Review

Congenital infections represent a challenging and varied clinical scenario in which the brain is frequently involved. Therefore, fetal and neonatal neuro-imaging plays a pivotal role in reaching an accurate diagnosis and in predicting the clinical outcome. Congenital brain infections are characterized by various clinical manifestations, ranging from nearly asymptomatic diseases to syndromic disorders, often associated with severe neurological symptoms. Brain damage results from the complex interaction among the infectious agent, its specific cellular tropism, and the stage of development of the central nervous system at the time of the maternal infection. Therefore, neuroradiological findings vary widely and are the result of complex events. An early detection is essential to establishing a proper diagnosis and prognosis, and to guarantee an optimal and prompt therapeutic perinatal management. Recently, emerging infective agents (i.e., Zika virus and SARS-CoV2) have been related to possible pre- and perinatal brain damage, thus expanding the spectrum of congenital brain infections. The purpose of this pictorial review is to provide an overview of the current knowledge on fetal and neonatal brain neuroimaging patterns in congenital brain infections used in clinical practice.

Emerging Concepts in Congenital Cytomegalovirus

Over a century of research has focused on improving our understanding of congenital cytomegalovirus (cCMV), yet it remains the most common congenital infection in the United States, affecting 3 to 6 per 1000 live born infants each year. Pregnancies affected by cCMV are at a heightened risk of spontaneous abortion and intrauterine fetal demise. Neonates born with cCMV are also at substantial risk for long-term neurodevelopmental sequelae and disability, including sensorineural hearing loss, even those born without clinically apparent disease. Considerable progress has been made in recent years in study of the epidemiology and transmission of cCMV, developing better diagnostic strategies, implementing newborn screening programs, improving therapeutics, and launching vaccine trials. In this article, we review recent developments in the understanding of the virology and immunobiology of cytomegalovirus. We further discuss how this knowledge informs our understanding of the pathophysiology of cCMV and directs strategies aimed at improving outcomes and quality of life for congenitally infected children. We also provide an update on the epidemiology of cCMV in the United States, evolving scientific understanding of maternal-fetal transmission, enhanced screening approaches, and recognition of neonatal and long-term sequelae. Finally, we review the current landscape of pediatric cCMV research and provide recommendations for novel and high-priority areas for future investigation.

Development of broadly neutralizing antibodies targeting the cytomegalovirus subdominant antigen gH

Human cytomegalovirus (HCMV) is a β-herpesvirus that increases morbidity and mortality in immunocompromised individuals including transplant recipients and newborns. New anti-HCMV therapies are an urgent medical need for diverse patient populations. HCMV infection of a broad range of host tissues is dependent on the gH/gL/gO trimer and gH/gL/UL28/UL130/UL131A pentamer complexes on the viral envelope. We sought to develop safe and effective therapeutics against HCMV by generating broadly-neutralizing, human monoclonal antibodies (mAbs) from VelocImmune® mice immunized with gH/gL cDNA. Following high-throughput binding and neutralization screening assays, 11 neutralizing antibodies were identified with unique CDR3 regions and a high-affinity (KD 1.4-65 nM) to the pentamer complex. The antibodies bound to distinct regions within Domains 1 and 2 of gH and effectively neutralized diverse clinical strains in physiologically relevant cell types including epithelial cells, trophoblasts, and monocytes. Importantly, combined adminstration of mAbs with ganciclovir, an FDA approved antiviral, greatly limited virus dissemination. Our work identifies several anti-gH/gL mAbs and sheds light on gH neutralizing epitopes that can guide future vaccine strategies.

Cranial ultrasound and MRI: complementary or not in the diagnostic assessment of children with congenital CMV infection?

Whether or not cranial ultrasound (crUS) and cerebral magnetic resonance imaging (MRI) have both a place in the assessment of children with congenital cytomegalovirus infection (cCMV) remains a topic of discussion between research groups. Literature suggests that MRI is indicated only in children with abnormal crUS.In Flanders, Belgium, combined crUS and MRI was performed on 639 children with cCMV, referred for diagnostic assessment. Cranial US was classified as abnormal in the presence of striatal vasculopathy, calcifications, cysts, cystic germinolysis, and/or ventriculomegaly. MRI findings were classified as abnormal in the presence of gyration disorders, cerebellar abnormalities, ventriculomegaly, cysts, or pathologic white matter lesions.One in five children (93/480) with normal crUS showed abnormal findings on MRI. Of them, 85 (91.4%) were classified as symptomatic. In 37 of those 93 children (39.8%), classification as severely symptomatic was made based on MRI lesions alone. MRI and crUS proved to be complementary in the assessment of CNS involvement in children with cCMV. Long-term studies are needed to evaluate the importance of this finding with respect to outcome and benefit of therapy in this particular subgroup of patients with cCMV infection.Conclusion: Our findings support an enhanced role of MRI in the diagnosis of CNS involvement in children with cCMV infection. The ideal assessment should include both imaging techniques, as the strengths of each test compensate for the other's weaknesses. What is Known: • Congenital CMV infection involves the central nervous system with direct injury to and possible disruption of brain development. • Experts suggest that MRI is indicated only in children with abnormal crUS. What is New: • In almost 20% of our children with a normal cranial ultrasound, abnormalities were detected on MRI. • Our results suggest that performing both MRI and cranial US is important to obtain a complete assessment of central nervous system involvement in children with cCMV.

Congenital CMV-Associated Hearing Loss: Can Brain Imaging Predict Hearing Outcome?

OBJECTIVES

Congenital cytomegalovirus (cCMV) infection is the leading cause of nonhereditary sensorineural hearing loss in childhood and is also associated with CNS abnormalities. The main objective is to investigate the prognostic value of neonatal cranial ultrasound (cUS) and cranial magnetic resonance imaging (cMRI) in predicting long-term hearing outcome in a large cohort of cCMV-infected symptomatic and asymptomatic patients.

DESIGN

Data were prospectively collected from a multicentre Flemish registry of children with cCMV infection born between 2007 and 2016. Neonatal cUS and cMRI scans were examined for lesions related to cCMV infection. Audiometric results at different time points were analyzed. The imaging and audiometric results were linked and diagnostic values of cUS and cMRI were calculated for the different hearing outcomes.

RESULTS

We were able to include 411 cCMV patients, of whom 40% was considered symptomatic at birth. Cranial ultrasound abnormalities associated with cCMV infection were found in 76 children (22.2% of the cUS scans), whereas cMRI revealed abnormalities in 74 patients (26.9% of the cMRI scans). A significant relation could be found between the presence of cUS or cMRI abnormalities and hearing loss at baseline and last follow-up. Cranial ultrasound and cMRI findings were not significantly correlated with the development of delayed-onset hearing loss. Specificity and sensitivity of an abnormal cUS to predict hearing loss at final follow-up were 84% and 43%, respectively compared with 78% and 39% for cMRI. Normal cUS and cMRI findings have a negative predictive value of 91% and 92%, respectively, for the development of delayed-onset hearing loss.

CONCLUSIONS

Neuroimaging evidence of CNS involvement in the neonatal period is associated with the presence of hearing loss in children with a cCMV infection. Imaging abnormalities are not predictive for the development of delayed-onset hearing loss.

Hygiene promotion might be better than serological screening to deal with Cytomegalovirus infection during pregnancy: a methodological appraisal and decision analysis

BACKGROUND

Cytomegalovirus infection is the most frequent viral congenital infection, with possible consequences such as deafness, or psychomotor retardation. In 2016, the French High Council of Public Health was mandated to update recommendations regarding prevention of cytomegalovirus infection in pregnant women. We summarize a critical appraisal of knowledge and deterministic decision analysis comparing the current no-screening situation to serological screening during pregnancy, and to hygiene promotion.

METHODS

Screening was defined as systematic serological testing, during the first trimester, with repeated tests as needed, to all pregnant women. Outcomes were: 1) severe sequela: intellectual deficiency with IQ ≤ 50 or hearing impairment < 70 dB or sight impairment (≤ 3/10 at best eye); 2) moderate sequela: any level of intellectual, hearing or sight deficiency; and 3) death or termination of pregnancy. We simulated the one-year course of cytomegalovirus infection in a cohort of 800,000 pregnant women. We developed a deterministic decision model, using best and min-max estimates, extracted from systematic reviews or original studies.

RESULTS

Relevant data were scarce or imprecise. We estimated that 4352 maternal primary infections would result in 1741 foetal infections, and an unknown number of maternal reinfections would result in 1699 foetal infections. There would be 788 cytomegalovirus-related consequences, including 316 foetal deaths or terminations of pregnancy, and 424 moderate and 48 severe sequelae. Screening would result in a 1.66-fold increase of poor outcomes, mostly related to a 2.93-fold increase in deaths and terminations of pregnancy, not compensated by the decrease in severe symptomatic newborns. The promotion of hygiene would result in a 0.75-fold decrease of poor outcomes, related to both a decrease in severe sequelae among symptomatic newborns (RR = 0.75; min-max: 1.00-0.68), and in deaths and terminations of pregnancy (RR = 0.75; min-max: 0.97-0.68).

CONCLUSIONS

Prevention of cytomegalovirus infection during pregnancy should promote hygiene; serological screening should not be recommended.

A new MRI severity score to predict long-term adverse neurologic outcomes in children with congenital Cytomegalovirus infection

BACKGROUND

Congenital cytomegalovirus (CMV) infection is one of the main causes of deafness in childhood. It frequently causes serious long-term neurological sequelae. In children who are asymptomatic at birth, tests to accurately predict these sequelae are still unavailable.

AIMS

We describe different brain MRI patterns of congenital CMV infection correlated with clinical data and propose a new MRI severity score to early predict long-term neurological sequelae.

MATERIALS AND METHODS

We explored clinical records and neuroimaging data of 224 neonates and children with congenital Cytomegalovirus infection, 180 of them did not meet inclusion criteria. Forty-four babies met inclusion criteria and were enrolled in the study. We retrospectively collected clinical data concerning hospitalization, 2 years outpatient follow-up and brain MRI findings of those 44 children, symptomatic and asymptomatic at birth. Clinical data were then correlated with children's brain MRI examinations. We defined neurological and sensorial impairment (hearing or visual) as "adverse neurological outcomes". Brain MRI score was constructed assigning different values to white matter and ventricular dilation.

RESULTS

In 44 children enrolled in the study we found that 28/35 (80%) with abnormal and 2/9 (22,2%) with normal MRI examination developed adverse neurological outcomes (OR = 3.6) (95% IC 1.0-12.0). Infants who were symptomatic at birth showed a probability of MRI brain lesions 3.2 times higher than those who were asymptomatic. Ten out of 17 (59%) children who were asymptomatic at birth showed MRI-WM alterations or ventriculomegaly.

CONCLUSIONS

Brain MRI abnormalities, such as WM alterations and ventriculomegaly, expressed as MRI score higher than 2 are associated with an increased probability of long-term adverse neurological outcome in congenitally CMV infected infants, symptomatic and asymptomatic at birth.

Neuroimaging Profiles and Neurodevelopmental Outcome in Infants With Congenital Cytomegalovirus Infection

BACKGROUND

The accurate stratification of infants with congenital cytomegalovirus (CMV) infection at risk for more severe outcome may help in the management of patients. Aim of this study was to investigate the ability of a comprehensive neuroimaging investigation in predicting the long-term neurodevelopmental outcome in patients with congenital CMV. We analyzed the prognostic accuracy of a traditional score and a recently proposed scale applied to head ultrasound (HUS), computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

All consecutive neonates born from 2002 to 2015 with congenital CMV infection were considered eligible for the study. Neuroimaging findings were scored according to both scores.

RESULTS

One hundred seventy infants were included (112 symptomatic patients). One-hundred eighteen infants received both HUS, CT and MRI. CT and MRI were normal in all 56 asymptomatic patients, while 32% of them presented an abnormal HUS. The prevalence of abnormal findings differed according to the neuroimaging study. The sensitivity of the new neuroimaging score in detecting patients at risk for poor neurologic outcome was higher than the traditional one for all neuroimaging examinations. CT and MRI showed higher positive predictive value compared with HUS. No neuroimaging examination showed a negative predictive value equal to 100%.

CONCLUSIONS

Although HUS is the safest neuroimaging technique, it performs less well in detecting some brain abnormalities that can be associated with a poor neurodevelopmental outcome. A comprehensive neuroimaging evaluation is mandatory in infants with congenital CMV infection to decide for treatment and make a prognostic evaluation.

Imaging the term neonatal brain

Brain imaging is important for the diagnosis and management of sick term neonates. Although ultrasound and computed tomography may provide some information, magnetic resonance imaging is now the brain imaging modality of choice because it is the most sensitive technique for detecting and quantifying brain abnormalities and does not expose infants to radiation. This statement describes the principles, roles and limitations of these three imaging modalities and makes recommendations for appropriate use in term neonates. The primary focus is the brain of term infants with neonatal encephalopathy, many of whom are diagnosed with hypoxic-ischemic encephalopathy.

Hearing Trajectory in Children with Congenital Cytomegalovirus Infection

Objectives To compare hearing trajectories among children with symptomatic and asymptomatic congenital cytomegalovirus infection through age 18 years and to identify brain abnormalities associated with sensorineural hearing loss (SNHL) in asymptomatic case patients. Study Design Longitudinal prospective cohort study. Setting Tertiary medical center. Subjects and Methods The study included 96 case patients (4 symptomatic and 92 asymptomatic) identified through hospital-based newborn cytomegalovirus screening from 1982 to 1992 and 72 symptomatic case patients identified through referrals from 1993 to 2005. We used growth curve modeling to analyze hearing thresholds (0.5-8 kHz) by ear with increasing age and Cox regression to determine abnormal findings on head computed tomography scan associated with SNHL (hearing threshold ≥25 dB in any audiometric frequency) among asymptomatic case patients. Results Fifty-six (74%) symptomatic and 20 (22%) asymptomatic case patients had SNHL: congenital/early-onset SNHL was diagnosed in 78 (51%) and 10 (5%) ears, respectively, and delayed-onset SNHL in 25 (17%) and 20 (11%) ears; 49 (32%) and 154 (84%) ears had normal hearing. In affected ears, all frequency-specific hearing thresholds worsened with age. Congenital/early-onset SNHL was significantly worse (severe-profound range, >70 dB) than delayed-onset SNHL (mild-moderate range, 26-55 db). Frequency-specific hearing thresholds were significantly different between symptomatic and asymptomatic case patients at 0.5 to 1 kHz but not at higher frequencies (2-8 kHz). Among asymptomatic case patients, white matter lucency was significantly associated with SNHL by age 5 years (hazard ratio, 4.4; 95% CI, 1.3-15.6). Conclusion Congenital/early-onset SNHL frequently resulted in severe to profound loss in symptomatic and asymptomatic case patients. White matter lucency in asymptomatic case patients was significantly associated with SNHL by age 5 years.

Valganciclovir Use Among Commercially and Medicaid-insured Infants With Congenital CMV Infection in the United States, 2009-2015

PURPOSE

The aim of this study was to assess the clinical characteristics and trends in valganciclovir use among infants diagnosed with congenital cytomegalovirus (CMV) disease in the United States.

METHODS

We analyzed data from medical claims dated 2009-2015 from the Truven Health MarketScan^® Commercial Claims and Encounters and Medicaid databases. We identified infants with a live birth code in the first claim who were continuously enrolled for at least 45 days. Among infants diagnosed with congenital CMV disease, identified by an ICD-9-CM or ICD-10-CM code for congenital CMV infection or CMV disease within 45 days of birth, we assessed data from claims containing codes for any CMV-associated clinical condition within the same period, and data from claims for hearing loss and/or valganciclovir within the first 180 days of life.

FINDINGS

In the commercial and Medicaid databases, we identified 257 (2.5/10,000) and 445 (3.3/10,000) infants, respectively, diagnosed with congenital CMV disease, among whom 135 (53%) and 282 (63%) had ≥1 CMV-associated condition, 30 (12%) and 32 (7%) had hearing loss, and 41 (16%) and 78 (18%) had a claim for valganciclovir. Among infants with congenital CMV disease who had a claim for valganciclovir, 37 (90%) among commercially insured infants and 68 (87%) among Medicaid-insured infants had ≥1 CMV-associated condition and/or hearing loss. From 2009 to 2015, the percentages with a claim for valganciclovir increased from 0% to 29% among commercially insured infants and from 4% to 37% among Medicaid-insured infants (P < 0.0001).

IMPLICATIONS

During 2009-2015, there was a strong upward trend in valganciclovir claims among insured infants who were diagnosed with congenital CMV disease, the majority of whom had CMV-associated conditions and/or hearing loss.

Long-term outcomes of children with symptomatic congenital cytomegalovirus disease

OBJECTIVE

To assess long-term outcomes of children with symptomatic congenital cytomegalovirus (CMV) disease detected at birth.

STUDY DESIGN

We used Cox regression to assess risk factors for intellectual disability (intelligence quotient <70), sensorineural hearing loss (SNHL; hearing level ⩾25 dB in any audiometric frequency) and vision impairment (best corrected visual acuity >20 or based on ophthalmologist report).

RESULTS

Among 76 case-patients followed through median age of 13 (range: 0-27) years, 56 (74%) had SNHL, 31 (43%, n=72) had intellectual disability and 18 (27%, n=66) had vision impairment; 28 (43%, n=65) had intellectual disability and SNHL with/without vision impairment. Microcephaly was significantly associated with each of the three outcomes. Tissue destruction and dysplastic growth on head computed tomography scan at birth was significantly associated with intellectual disability and SNHL.

CONCLUSION

Infants with symptomatic congenital CMV disease may develop moderate to severe impairments that were associated with presence of microcephaly and brain abnormalities.

Tumor Necrosis Factor Alpha-Induced Recruitment of Inflammatory Mononuclear Cells Leads to Inflammation and Altered Brain Development in Murine Cytomegalovirus-Infected Newborn Mice

Congenital human cytomegalovirus (HCMV) infection is a significant cause of abnormal neurodevelopment and long-term neurological sequelae in infants and children. Resident cell populations of the developing brain have been suggested to be more susceptible to virus-induced cytopathology, a pathway thought to contribute to the clinical outcomes following intrauterine HCMV infection. However, recent findings in a newborn mouse model of the infection in the developing brain have indicated that elevated levels of proinflammatory mediators leading to mononuclear cell activation and recruitment could underlie the abnormal neurodevelopment. In this study, we demonstrate that treatment with tumor necrosis factor alpha (TNF-α)-neutralizing antibodies decreased the frequency of CD45⁺ Ly6C^hi CD11b⁺ CCR2⁺ activated myeloid mononuclear cells (MMCs) and the levels of proinflammatory cytokines in the blood and the brains of murine CMV-infected mice. This treatment also normalized neurodevelopment in infected mice without significantly impacting the level of virus replication. These results indicate that TNF-α is a major component of the inflammatory response associated with altered neurodevelopment that follows murine CMV infection of the developing brain and that a subset of peripheral blood myeloid mononuclear cells represent a key effector cell population in this model of virus-induced inflammatory disease of the developing brain.IMPORTANCE Congenital human cytomegalovirus (HCMV) infection is the most common viral infection of the developing human fetus and can result in neurodevelopmental sequelae. Mechanisms of disease leading to neurodevelopmental deficits in infected infants remain undefined, but postulated pathways include loss of neuronal progenitor cells, damage to the developing vascular system of the brain, and altered cellular positioning. Direct virus-mediated cytopathic effects cannot explain the phenotypes of brain damage in most infected infants. Using a mouse model that recapitulates characteristics of the brain infection described in human infants, we have shown that TNF-α plays a key role in brain inflammation, including recruitment of inflammatory mononuclear cells. Neutralization of TNF-α normalized neurodevelopmental abnormalities in infected mice, providing evidence that virus-induced inflammation is a major component of disease in the developing brain. These results suggest that interventions limiting inflammation associated with the infection could potentially improve the neurologic outcome of infants infected in utero with HCMV.

Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia

Classical lissencephaly is a genetic neurological disorder associated with mental retardation and intractable epilepsy, and Miller-Dieker syndrome (MDS) is the most severe form of the disease. In this study, to investigate the effects of MDS on human progenitor subtypes that control neuronal output and influence brain topology, we analyzed cerebral organoids derived from control and MDS-induced pluripotent stem cells (iPSCs) using time-lapse imaging, immunostaining, and single-cell RNA sequencing. We saw a cell migration defect that was rescued when we corrected the MDS causative chromosomal deletion and severe apoptosis of the founder neuroepithelial stem cells, accompanied by increased horizontal cell divisions. We also identified a mitotic defect in outer radial glia, a progenitor subtype that is largely absent from lissencephalic rodents but critical for human neocortical expansion. Our study, therefore, deepens our understanding of MDS cellular pathogenesis and highlights the broad utility of cerebral organoids for modeling human neurodevelopmental disorders.

Primary maternal cytomegalovirus infections: accuracy of fetal ultrasound for predicting sequelae in offspring

BACKGROUND

Cytomegalovirus infection is the most common perinatal viral infection that can lead to severe long-term medical conditions. Antenatal identification of maternal cytomegalovirus infections with proven fetal transmission and potential postnatal clinical sequelae remains a major challenge in perinatology. There is a need to improve the prenatal counseling offered to patients and guide future clinical management decisions in cases of proven primary cytomegalovirus infection.

OBJECTIVE

We sought to evaluate the accuracy of fetal ultrasound for predicting sequelae in fetuses infected with congenital cytomegalovirus after maternal primary infection.

STUDY DESIGN

We conducted a prospective observational study from 1996 through 2012 in pregnant women with serological evidence of primary cytomegalovirus infection and proven vertical transmission to the fetus, based on viral load in the amniotic fluid. Fetal ultrasound was performed in all patients. Pregnancy termination was presented as an option for infected fetuses. Hearing and neurological clinical assessments were performed for all neonates with cytomegalovirus-positive urine samples.

RESULTS

A total of 67 patients (69 fetuses) with proven vertical transmission were included in this study, including 64 singleton and 3 twin pregnancies. Eight fetuses were lost to follow-up. Of the remaining 61 fetuses, termination of the pregnancy was performed for 26, including 11 with fetal ultrasound anomalies. Autopsy provided histological evidence of fetal cytomegalovirus infection in all cases. In the 15 terminated fetuses without ultrasound anomalies, histological evidence of damage caused by fetal infection was detected in 13 cases. Among the 35 live-born infants, 12 had fetal ultrasound anomalies suggestive of congenital infection. Of these 12 infants, 6 had normal clinical evaluations, whereas 6 presented with either hearing and/or neurological anomalies, classified as severe in 4 cases. Among the 23 live-born infants with normal prenatal ultrasound, 5 developed hearing impairments and 1 showed mild neurological developmental delay.

CONCLUSION

Fetal ultrasound anomalies were detected in 37.7% of pregnant women with primary cytomegalovirus infection acquired in early pregnancy and proven fetal infection, and were confirmed by autopsy or postnatal clinical evaluation in 73.9%. Autopsy or postnatal clinical evaluation also detected cytomegalovirus-related anomalies in 55% of infants with normal fetal ultrasound evaluations.

Diffuse periventricular calcification and brain atrophy: A case of neonatal central nervous system cytomegalovirus infection

TORCH refers to the most common congenitally acquired infections: toxoplasma, rubella, cytomegalovirus, and herpes simplex virus. Neonatal cytomegalovirus infection remains a common cause of congenital infection worldwide with effects ranging from hearing impairment to significant neurological morbidity. We report a case of a term neonate with ventriculomegaly on prenatal ultrasound who presented with low birth weight, small head circumference, hepatosplenomegaly, and purpuric rash on physical exam. Central nervous system cytomegalovirus infection typically shows periventricular calcifications and associated deep white matter damage and ventriculomegaly. Ultrasound, computed tomography, and magnetic resonance imaging have different roles in the diagnosis of congenital central nervous system cytomegalovirus infection. Many imaging features of congenital cytomegalovirus are distinctive, and can spur a diagnostic work-up as well as help provide a prognosis.

Expression Analysis Highlights AXL as a Candidate Zika Virus Entry Receptor in Neural Stem Cells

The recent outbreak of Zika virus (ZIKV) in Brazil has been linked to substantial increases in fetal abnormalities and microcephaly. However, information about the underlying molecular and cellular mechanisms connecting viral infection to these defects remains limited. In this study we have examined the expression of receptors implicated in cell entry of several enveloped viruses including ZIKV across diverse cell types in the developing brain. Using single-cell RNA-seq and immunohistochemistry, we found that the candidate viral entry receptor AXL is highly expressed by human radial glial cells, astrocytes, endothelial cells, and microglia in developing human cortex and by progenitor cells in developing retina. We also show that AXL expression in radial glia is conserved in developing mouse and ferret cortex and in human stem cell-derived cerebral organoids, highlighting multiple experimental systems that could be applied to study mechanisms of ZIKV infectivity and effects on brain development.

Detection and sequencing of Zika virus from amniotic fluid of fetuses with microcephaly in Brazil: a case study

BACKGROUND

The incidence of microcephaly in Brazil in 2015 was 20 times higher than in previous years. Congenital microcephaly is associated with genetic factors and several causative agents. Epidemiological data suggest that microcephaly cases in Brazil might be associated with the introduction of Zika virus. We aimed to detect and sequence the Zika virus genome in amniotic fluid samples of two pregnant women in Brazil whose fetuses were diagnosed with microcephaly.

METHODS

In this case study, amniotic fluid samples from two pregnant women from the state of Paraíba in Brazil whose fetuses had been diagnosed with microcephaly were obtained, on the recommendation of the Brazilian health authorities, by ultrasound-guided transabdominal amniocentesis at 28 weeks' gestation. The women had presented at 18 weeks' and 10 weeks' gestation, respectively, with clinical manifestations that could have been symptoms of Zika virus infection, including fever, myalgia, and rash. After the amniotic fluid samples were centrifuged, DNA and RNA were extracted from the purified virus particles before the viral genome was identified by quantitative reverse transcription PCR and viral metagenomic next-generation sequencing. Phylogenetic reconstruction and investigation of recombination events were done by comparing the Brazilian Zika virus genome with sequences from other Zika strains and from flaviviruses that occur in similar regions in Brazil.

FINDINGS

We detected the Zika virus genome in the amniotic fluid of both pregnant women. The virus was not detected in their urine or serum. Tests for dengue virus, chikungunya virus, Toxoplasma gondii, rubella virus, cytomegalovirus, herpes simplex virus, HIV, Treponema pallidum, and parvovirus B19 were all negative. After sequencing of the complete genome of the Brazilian Zika virus isolated from patient 1, phylogenetic analyses showed that the virus shares 97-100% of its genomic identity with lineages isolated during an outbreak in French Polynesia in 2013, and that in both envelope and NS5 genomic regions, it clustered with sequences from North and South America, southeast Asia, and the Pacific. After assessing the possibility of recombination events between the Zika virus and other flaviviruses, we ruled out the hypothesis that the Brazilian Zika virus genome is a recombinant strain with other mosquito-borne flaviviruses.

INTERPRETATION

These findings strengthen the putative association between Zika virus and cases of microcephaly in neonates in Brazil. Moreover, our results suggest that the virus can cross the placental barrier. As a result, Zika virus should be considered as a potential infectious agent for human fetuses. Pathogenesis studies that confirm the tropism of Zika virus for neuronal cells are warranted.

FUNDING

Consellho Nacional de Desenvolvimento e Pesquisa (CNPq), Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ).

Risk of congenital disease in 46 infected fetuses according to gestational age of primary human cytomegalovirus infection in the mother

Given the difficulty in establishing the exact time of HCMV transmission from mother to fetus, HCMV intrauterine infection was investigated in 46 infected fetuses/newborns by correlating maternal and fetal parameters with clinical outcome according to the time interval between the onset of maternal infection and prenatal diagnosis. In detail, 17/28 (60.7%) asymptomatic and 18/18 (100%) symptomatic fetuses/newborns were infected as a consequence of a primary maternal HCMV infection acquired ≤8 weeks of gestational age, while 11/28 (39.3%) asymptomatic and 0/18 (0%) symptomatic fetuses/newborns were congenitally infected when maternal infection was acquired >8 weeks' gestation. Symptomatic fetal infections appeared to be associated with a maternal primary infection occurring at ≤ 8 weeks' gestation. Cordocentesis performed at 20 weeks' gestation should be restricted to high risk infected fetuses.

Evolutive leukoencephalopathy in congenital cytomegalovirus infection

Congenital cytomegalovirus infection is the most common infectious cause of congenital brain injury. Type and severity of congenital cytomegalovirus infection-related brain abnormalities depend on the developmental stage of the central nervous system at the time of fetal infection. The aim of this study was to follow the course of leukoencephalopathy in a patient with congenital cytomegalovirus infection. We describe brain magnetic resonance imaging (MRI) findings of a boy with symptomatic congenital cytomegalovirus infection performed at the age of 3 weeks, 13 months, and 4 and 7 years. Neonatal brain MRI showed most of characteristic findings in congenital cytomegalovirus infection with most prominent white matter abnormalities and cortical dysplasia. MRI follow-up images showed that cortical dysgenesis remained unchanged and static, whereas white matter abnormalities evolved over the years. We propose that leukoencephalopathy in congenital cytomegalovirus infection is not only nonprogressive or static but even evolutive and suggests both underlying disruption and delay of myelination.

Neuro-imaging findings in infants with congenital cytomegalovirus infection: relation to trimester of infection

BACKGROUND

Congenital cytomegalovirus (cCMV) infection early in pregnancy may result in major disabilities. Cerebral abnormalities detected using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) have been related to neurological sequelae.

OBJECTIVE

To evaluate the additional value of MRI and assess the relationship between time of infection during pregnancy and outcome in infants with cCMV infection.

METHODS AND STUDY DESIGN

Demographic and clinical data were collected in infants with cCMV infection (1992-2013). Trimester of infection, neuro-imaging results and outcome were reviewed. Cerebral abnormalities were categorized into none, mild (lenticulostriate vasculopathy, germinolytic cysts, high signal intensity on T2-weighted images) and severe (migrational disorder, ventriculomegaly, cerebellar hypoplasia). Results were statistically analysed.

RESULTS

Thirty-six infants were eligible for analysis. cUS was performed in all and cranial MRI in 20 infants. Migrational disorders were only diagnosed using MRI (p < 0.01). In 17 infants trimester of infection was ascertained. Seven out of 10 infants infected during the first trimester had severe abnormalities on cUS (5 confirmed on MRI) and adverse sequelae; 3 had no/mild abnormalities on cUS/MRI and normal outcome. Two out of 3 infants infected during the second trimester with no/mild abnormalities on cUS/MRI had normal outcome; 1 with mild cUS and MRI abnormalities developed sensorineural hearing loss. Four infants infected during the third trimester with no/mild abnormalities on cUS/MRI had normal outcome.

CONCLUSION

Infants with a first trimester cCMV infection are most at risk of severe cerebral abnormalities and neurological sequelae. MRI, and not cUS, enables an early diagnosis of migrational disorders, which can improve prediction of outcome.

Diagnosis and counseling of fetal and neonatal HCMV infection

Fetal HCMV infection is investigated by amniocentesis when a maternal primary infection is diagnosed or ultrasound (US/MRI) abnormalities are observed. In fetal blood, prognostic markers of symptomatic congenital infection may be evaluated for parental counseling. At birth, viral load measurement in body fluids may correlate with long-term sequelae, but the prognostic accuracy of symptomatic infection increases when maternal, fetal, and neonatal parameters are combined.

Cytomegalovirus in the neonate: immune correlates of infection and protection

Fetal and neonatal infections caused by human cytomegalovirus (CMV) are important causes of morbidity and occasional mortality. Development of a vaccine against congenital CMV infection is a major public health priority. Vaccine design is currently focused on strategies that aim to elicit neutralizing antibody and T-cell responses, toward the goal of preventing primary or recurrent infection in women of child-bearing age. However, there has been relatively little attention given to understanding the mechanisms of immune protection against acquisition of CMV infection in the fetus and newborn and how this information might be exploited for vaccine design. There has similarly been an insufficient study of what deficits in the immune response to CMV, both for mother and fetus, may increase susceptibility to congenital infection and disease. Protection of the fetus against vertical transmission can likely be achieved by protection of the placenta, which has its own unique immunological milieu, further complicating the analysis of the correlates of protective immunity. In this review, the current state of knowledge about immune effectors of protection against CMV in the maternal, placental, and fetal compartments is reviewed. A better understanding of immune responses that prevent and/or predispose to infection will help in the development of novel vaccine strategies.

Congenital cytomegalovirus infection: new prospects for prevention and therapy

Cytomegalovirus is the commonest congenital viral infection in the developed world, with an overall prevalence of approximately 0.6%. Approximately 10% of congenitally infected infants have signs and symptoms of disease at birth, and these symptomatic infants have a substantial risk of subsequent neurologic sequelae. These include sensorineural hearing loss, mental retardation, microcephaly, development delay, seizure disorders, and cerebral palsy. Antiviral therapy for children with symptomatic congenital cytomegalovirus infection is effective at reducing the risk of long-term disabilities and should be offered to families with affected newborns. An effective preconceptual vaccine against CMV could protect against long-term neurologic sequelae and other disabilities.