Association Between Neonatal Neuroimaging and Clinical Outcomes in Zika-Exposed Infants From Rio de Janeiro, Brazil

Integrative analysis of molecular pathways and morphological anomalies associated with congenital Zika syndrome

Congenital Zika syndrome (CZS) comprises a set of clinical manifestations that can be presented by neonates born to mothers infected by the Zika virus (ZIKV). CZS-associated phenotypes include neurological, skeletal, and systemic alterations and long-term developmental sequelae. One of the most frequently reported clinical conditions is microcephaly characterized by a reduction in head circumference and cognitive complications. Nevertheless, the associations among the diverse signaling pathways underlying CZS phenotypes remain to be elucidated. To shed light on CZS, we have extensively reviewed the morphological anomalies resulting from ZIKV infection, as well as genes and proteins of interest obtained from the published literature. With this list of genes or proteins, we performed computational analyses to explore the cellular processes, molecular mechanisms, and molecular pathways related to ZIKV infection. Therefore, in this review, we comprehensively describe the morphological abnormalities caused by congenital ZIKV infection and, through the analysis noted above, propose common molecular pathways altered by ZIKV that could explain both central nervous system and craniofacial skeletal alterations.

Understanding the multidimensional neurodevelopmental outcomes in children after congenital Zika virus exposure

Since 2016, international research groups have focused on assessing outcomes of children with in utero Zika virus (ZIKV) exposure. While the more severe outcomes of congenital Zika syndrome (CZS) occur in up to 10% of children with antenatal exposure, early findings among ZIKV-exposed children without CZS ages 0-5 years suggest that they may also have differences in multiple domains of neurodevelopment. Thus, longitudinal follow-up of all children with antenatal ZIKV exposure has been recommended. This review presents a summary of neurodevelopmental phenotypes of infants and children following antenatal ZIKV exposure. We present a multidimensional framework to understand child neurodevelopment from an interdisciplinary and whole-child perspective (International Classification of Functioning, Disability and Health model) and multi-domain ZIKV Outcome Toolboxes. The toolboxes are for clinicians, researchers, child educators, and others to implement longitudinal multi-domain neurodevelopmental assessments between ages 0-12 years. Recent innovations in telehealth and neuroimaging can help evaluate outcomes in ZIKV exposed children. The objective is to describe the multiple facets of neurodevelopmental focused care that can support the health, function, and well-being of children with antenatal ZIKV exposure. The research and clinical follow-up strategies are applicable to ZIKV and other congenital infectious or environmental exposures that can impact child neurodevelopment. IMPACT: International longitudinal cohort studies have revealed a range of differences in neurodevelopment among children with antenatal Zika virus (ZIKV) exposure. A multidimensional and whole-child framework is necessary to understand the neurodevelopment of children with antenatal ZIKV exposure in relation to family life, community participation, and environment. Multi-domain toolboxes that utilize parent questionnaires and child evaluations are presented. These toolboxes can be used internationally alongside telehealth, brain imaging, and other innovations to improve understanding of child outcomes.

Sustained chronic inflammation and altered childhood vaccine responses in children exposed to Zika virus

BACKGROUND

Congenital Zika virus (ZIKV) infection leads to severe newborn abnormalities, but its long-term impact on childhood immunity is not well understood. This study aims to investigate the serum proteomics in children exposed to ZIKV during pregnancy to understand potential immunological consequences during early childhood.

METHODS

The study included ZIKV-exposed infants (ZEI) at birth (n = 42) and children exposed to ZIKV (ZEC) at two years of age (n = 20) exposed to ZIKV during pregnancy, as well as healthy controls. Serum proteomic analysis was performed on these groups to assess inflammation and immune profiles. Additionally, antibody titres against two common childhood vaccines, DTaP and MMR, were measured in healthy controls (n = 50) and ZEC (n = 92) to evaluate vaccine-induced immunity.

FINDINGS

Results showed elevated inflammation in ZEI with birth abnormalities. Among ZEC, despite most having normal clinical outcomes at two years, their serum proteomics indicated a bias towards Th1-mediated immune responses. Notably, ZEC displayed reduced anti-Diphtheria toxin and anti-Clostridium tetani IgG levels against DTaP and MMR vaccines. They also exhibited lower antibody titres particularly against Th2-biased DTaP vaccines, but not Th1-biased MMR vaccines.

INTERPRETATION

In conclusion, the study highlights the long-term immunological consequences of congenital ZIKV exposure. Heightened inflammation was observed in ZEI with abnormalities at birth, while ZEC maintained a chronic Th1-biased immune profile. The impaired response to Th2-biased vaccines raises concerns about lasting effects of ZIKV exposure on immune responses. Consequently, there is a need for continued longitudinal clinical monitoring to identify potential immune-related complications arising from prenatal exposure to ZIKV.

FUNDING

This work was partially funded by the National Institute of Allergy and Infectious Diseases (NIAID) and National Institute of Dental and Craniofacial Research (NIDCR).

Mechanistic insights into bone remodelling dysregulation by human viral pathogens

Bone-related diseases (osteopathologies) associated with human virus infections have increased around the globe. Recent findings have highlighted the intricate interplay between viral infection, the host immune system and the bone remodelling process. Viral infections can disrupt bone homeostasis, contributing to conditions such as arthritis and soft tissue calcifications. Osteopathologies can occur after arbovirus infections such as chikungunya virus, dengue virus and Zika virus, as well as respiratory viruses, such as severe acute respiratory syndrome coronavirus 2 and enteroviruses such as Coxsackievirus B. Here we explore how human viruses dysregulate bone homeostasis, detailing viral factors, molecular mechanisms, host immune response changes and bone remodelling that ultimately result in osteopathologies. We highlight model systems and technologies to advance mechanistic understanding of viral-mediated bone alterations. Finally, we propose potential prophylactic and therapeutic strategies, introduce 'osteovirology' as a research field highlighting the underestimated roles of viruses in bone-related diseases, and discuss research avenues for further investigation.

Virus as Teratogenic Agents

Viral infectious diseases are important causes of reproductive disorders, as abortion, fetal mummification, embryonic mortality, stillbirth, and congenital abnormalities in animals and in humans. In this chapter, we provide an overview of some virus, as important agents in teratology.We begin by describing the Zika virus, whose infection in humans had a very significant impact in recent years and has been associated with major health problems worldwide. This virus is a teratogenic agent in humans and has been classified as a public health emergency of international concern (PHEIC).Then, some viruses associated with reproductive abnormalities on animals, which have a significant economic impact on livestock, are described, as bovine herpesvirus, bovine viral diarrhea virus, Schmallenberg virus, Akabane virus, and Aino virus.For all viruses mentioned in this chapter, the teratogenic effects and the congenital malformations associated with fetus and newborn are described, according to the most recent scientific publications.

Congenital Zika Virus Syndrome: Microcephaly and Orofacial Anomalies

The progressive reappearance of Zika virus (ZIKV) infections since October 2013 and its circulation in >70 countries and territories (from French Polynesia to Brazil and other countries in the Americas, with sporadic spread in Europe and the East) has long been reported as a global public health emergency. ZIKV is a virus transmitted by arthropods (arboviruses), mainly by Aedes mosquitoes. ZIKV can also be transmitted to humans through mechanisms other than vector infection such as sexual intercourse, blood transfusions, and mother-to-child transmission. The latter mode of transmission can give rise to a severe clinical form called congenital Zika syndrome (CZS), which can result in spontaneous abortion or serious pathological alterations in the fetus such as microcephaly or neurological and orofacial anomalies. In this study, beside a succinct overview of the etiological, microbiological, and epidemiological aspects and modes of transmission of Zika virus infections, we have focused our attention on the pathogenetic and histopathological aspects in pregnancy and the pathogenetic and molecular mechanisms that can determine microcephaly, and consequently the clinical alterations, typical of the fetus and newborns, in a subject affected by CZS.

Predictors of Neurodevelopment in Microcephaly Associated with Congenital Zika Syndrome: A Prospective Study

The municipality of Salvador, situated in Brazil, distinguished itself as the epicenter of the emergence of microcephaly related to congenital manifestations of Zika syndrome. Despite the anticipated significant developmental setbacks in these children, research has indicated a varied range of outcomes, with certain instances even reflecting minimal developmental delay. Our objective was to pinpoint determinants that could forecast developmental anomalies in children diagnosed with microcephaly associated with congenital Zika syndrome (CZS).

METHODOLOGY

A forward-looking clinical and neurodevelopmental examination was conducted focusing on neonates diagnosed with microcephaly with CZS, birthed between September 2015 and April 2016 at the Hospital Geral Roberto Santos, in Salvador city. That infants were monitored up to their third year by a multiprofessional team. Child development was assessed using the composite Bayley III score. Undertaken by two blinded experts, cranial CT scan analysis was performed during the neonate period for the detection of brain abnormalities and to quantify ventricle enlargement, measured by Evans' index (EI).

RESULTS

Fifty newborns were evaluated with a median head circumference of 28 cm (interquartile range 27-31 cm). EI was associated with neurodevelopmental delay at three years and remained significant after adjustment for head circumference. A 0.1-point increase in EI was associated with a delay of 3.2 months in the receptive language (p = 0.016), 3.4 months in the expressive language (p = 0.016), 3.4 months in the cognitive (p = 0.016), 2.37 months in the gross motor (p = 0.026), and 3.1 months in the fine motor (p = 0.021) domains.

CONCLUSIONS

EI predicted neurodevelopmental delay in all Bayley domains in children with microcephaly associated with CZS.

Modulation of cellular machineries by Zika virus-encoded proteins

The strain of Zika virus (ZIKV) that circulated during the 2015 epidemic in Brazil has been associated with more than 2000 cases of microcephaly from September 2015 through November 2016. The viral genome determines the biology and pathogenesis of a virus and the virus employs its own gene products to evade host immune surveillance, manipulate cellular machineries, and establish efficient replication. Therefore, understanding the functions of virus-encoded protein not only aids the knowledge of ZIKV biology but also guides the development of anti-ZIKV drugs. In this review, we focus on 10 proteins encoded by ZIKV and summarize their functions in ZIKV replication and pathogenesis according to studies published in the past 6 years.

Diagnostic accuracy of prenatal imaging for the diagnosis of congenital Zika syndrome: Systematic review and meta-analysis

Objective

The aim of this study was to assess the accuracy of prenatal imaging for the diagnosis of congenital Zika syndrome.

Data sources

Medline (via Pubmed), PubMed, Scopus, Web of Science, and Google Scholar from inception to March 2022. Two researchers independently screened study titles and abstracts for eligibility.

Study eligibility criteria

Observational studies with Zika virus-infected pregnant women were included. The index tests included ultrasound and/or magnetic resonance imaging. The reference standard included (1) Zika infection-related perinatal death, stillbirth, and neonatal death within the first 48 h of birth, (2) neonatal intensive care unit admission, and (3) clinically defined adverse perinatal outcomes.

Synthesis methods

We extracted 2 × 2 contingency tables. Pooled sensitivity and specificity were estimated using the random-effects bivariate model and assessed the summary receiver operating characteristic (ROC) curve. Risk of bias was assessed using QUADAS 2 tool. The certainty of the evidence was evaluated with grading of recommendations.

Results

We screened 1,459 references and included 18 studies (2359 pregnant women, 347 fetuses with confirmed Zika virus infection). Twelve studies (67%) were prospective cohorts/case series, and six (37%) were retrospective cohort/case series investigations. Fourteen studies (78%) were performed in endemic regions. Ten studies (56%) used prenatal ultrasound only, six (33%) employed ultrasound and fetal MRI, and two studies (11%) used prenatal ultrasound and postnatal fetal MRI. A total of six studies (ultrasound only) encompassing 780 pregnant women (122 fetuses with confirmed Zika virus infection) reported relevant data for meta-analysis (gestation age at which ultrasound imagining was captured ranged from 16 to 34 weeks). There was large heterogeneity across studies regarding sensitivity (range: 12 to 100%) and specificity (range: 50 to 100%). Under a random-effects model, the summary sensitivity of ultrasound was 82% (95% CI, 19 to 99%), and the summary specificity was 97% (71 to 100%). The area under the ROC curve was 97% (95% CI, 72 to 100%), and the summary diagnostic odds ratio was 140 (95% CI, 3 to 7564, P < 0.001). The overall certainty of the evidence was "very low".

Conclusion

Ultrasound may be useful in improving the diagnostic accuracy of Zika virus infection in pregnancy. However, the evidence is still substantially uncertain due to the methodological limitations of the available studies. Larger, properly conducted diagnostic accuracy studies of prenatal imaging for the diagnosis of congenital Zika syndrome are warranted.

Systematic review registration

Identifier [CRD42020162914].

Prevalence of individual brain and eye defects potentially related to Zika virus in pregnancy in 22 U.S. states and territories, January 2016 to June 2017

During the Centers for Disease Control and Prevention's Zika Virus Response, birth defects surveillance programs adapted to monitor birth defects potentially related to Zika virus (ZIKV) infection during pregnancy. Pregnancy outcomes occurring during January 2016 to June 2017 in 22 U.S. states and territories were used to estimate the prevalence of those brain and eye defects potentially related to ZIKV. Jurisdictions were divided into three groups: areas with widespread ZIKV transmission, areas with limited local ZIKV transmission, and areas without local ZIKV transmission. Prevalence estimates for selected brain and eye defects and microcephaly per 10,000 live births were estimated. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated using Poisson regression for areas with widespread and limited ZIKV transmission compared with areas without local ZIKV transmission. Defects with significantly higher prevalence in areas of widespread transmission were pooled, and PRs were calculated by quarter, comparing subsequent quarters to the first quarter (January-March 2016). Nine defects had significantly higher prevalence in areas of widespread transmission. The highest PRs were seen in intracranial calcifications (PR = 12.6, 95% CI [7.4, 21.3]), chorioretinal abnormalities (12.5 [7.1, 22.3]), brainstem abnormalities (9.3 [4.7, 18.4]), and cerebral/cortical atrophy (6.7 [4.2, 10.8]). The PR of the nine pooled defects was significantly higher in three quarters in areas with widespread transmission. The largest difference in prevalence was observed for defects consistently reported in infants with congenital ZIKV infection. Birth defects surveillance programs could consider monitoring a subset of birth defects potentially related to ZIKV in pregnancy.

Longitudinal Follow-Up of Gross Motor Function in Children with Congenital Zika Virus Syndrome from a Cohort in Rio de Janeiro, Brazil

Knowledge of how congenital Zika syndrome (CZS) impacts motor development of children longitudinally is important to guide management. The objective of the present study was to describe the evolution of gross motor function in children with CZS in a Rio de Janeiro hospital. In children with CZS without arthrogryposis or other congenital osteoarticular malformations who were followed in a prospective cohort study, motor performance was evaluated at two timepoints using the Gross Motor Function Classification System (GMFCS) and the Gross Motor Function Measurement test (GMFM-88). Among 74 children, at the baseline evaluation, the median age was 13 (8–24) months, and on follow-up, 28 (24–48) months. According to GMFCS at the second timepoint, 6 children were classified as mild, 11 as moderate, and 57 as severe. In the GMFM-88 assessment, children in the severe group had a median score of 10.05 in the baseline evaluation and a follow-up score of 12.40, the moderate group had median scores of 25.60 and 29.60, and the mild group had median scores of 82.60 and 91.00, respectively. Although a small developmental improvement was observed, the motor impairment of children was mainly consistent with severe cerebral palsy. Baseline motor function assessments were predictive of prognosis.

Zika virus congenital microcephaly severity classification and the association of severity with neuropsychomotor development

BACKGROUND

Zika virus infection during pregnancy is linked to birth defects, most notably microcephaly, which is associated with neurodevelopmental delays.

OBJECTIVE

The goals of the study were to propose a method for severity classification of congenital microcephaly based on neuroradiologic findings of MRI scans, and to investigate the association of severity with neuropsychomotor developmental scores. We also propose a semi-automated method for MRI-based severity classification of microcephaly.

MATERIALS AND METHODS

We conducted a cross-sectional investigation of 42 infants born with congenital Zika infection. Bayley Scales of Infant and Toddler Development III (Bayley-III) developmental evaluations and MRI scans were carried out at ages 13-39 months (mean: 24.8 months; standard deviation [SD]: 5.8 months). The severity score was generated based on neuroradiologist evaluations of brain malformations. Next, we established a distribution of Zika virus-microcephaly severity score including mild, moderate and severe and investigated the association of severity with neuropsychomotor developmental scores. Finally, we propose a simplified semi-automated procedure for estimating the severity score based only on volumetric measures.

RESULTS

The results showed a correlation of r=0.89 (P<0.001) between the Zika virus-microcephaly severity score and the semi-automated method. The trimester of infection did not correlate with the semi-automated method. Neuropsychomotor development correlated with the severity classification based on the radiologic readings and semi-automated method; the more severe the imaging scores, the lower the neuropsychomotor developmental scores.

CONCLUSION

These severity classification methods can be used to evaluate severity of microcephaly and possible association with developmental consequences. The semi-automated methods thus provide an alternative for predicting severity of microcephaly based on only one MRI sequence.

Let's Get Physical: Flavivirus-Host Protein-Protein Interactions in Replication and Pathogenesis

Flaviviruses comprise a genus of viruses that pose a significant burden on human health worldwide. Transmission by both mosquito and tick vectors, and broad host tropism contribute to the presence of flaviviruses globally. Like all viruses, they require utilization of host molecular machinery to facilitate their replication through physical interactions. Their RNA genomes are translated using host ribosomes, synthesizing viral proteins that cooperate with each other and host proteins to reshape the host cell into a factory for virus replication. Thus, dissecting the physical interactions between viral proteins and their host protein targets is essential in our comprehension of how flaviviruses replicate and how they alter host cell behavior. Beyond replication, even single interactions can contribute to immune evasion and pathogenesis, providing potential avenues for therapeutic intervention. Here, we review protein interactions between flavivirus and host proteins that contribute to virus replication, immune evasion, and disease.

Early Predictors of Poor Neurologic Outcomes in a Prospective Cohort of Infants With Antenatal Exposure to Zika Virus

BACKGROUND

Identify early predictors of poor neurodevelopment in infants with antenatal Zika virus (ZIKV) exposure.

METHODS

Analysis of a prospective cohort of infants with antenatal ZIKV exposure confirmed by maternal or infant RT-PCR or IgM during the epidemic in Rio de Janeiro, Brazil. Clinical findings before 3 months of age were associated with Bayley-III Scales of Infant and Toddler Development conducted after 6 months of age.

RESULTS

ZIKV exposure was confirmed in 219 cases; 162 infants were normocephalic, 53 were microcephalic, 4 had no head circumference recorded because of perinatal death/LTFU. Seven of the 112 normocephalic infants developed secondary microcephaly between 3 weeks and 8 months of age. Among the normocephalic at birth cohort, the mean HCZ among normal, at risk, and developmentally delayed children was significantly different (ANOVA, P = 0.02). In particular, the mean HCZ of the developmentally delayed group was significantly lower than that of the normal group (Tukey's test, P = 0.014). HCZ was more strongly associated with lower expressive language scores (P = 0.04) than receptive language scores (P = 0.06). The rate of auditory abnormalities differed among the normal, at risk, and developmentally delayed groups (Chi-squared test, P = 0.016), which was driven by the significant difference between the normal and at risk groups (post hoc test, P = 0.011, risk ratio 3.94). Auditory abnormalities were associated with both expressive and receptive language delays (P = 0.02 and P = 0.02, respectively).

CONCLUSIONS

Clear predictors of neurodevelopment in normocephalic ZIKV-exposed children have not been previously identified. Our findings demonstrate that smaller HCZ and auditory abnormalities in these infants correlate with poor neurodevelopment as toddlers. Language delay is the most prominent developmental concern among these children, who will require frequent auditory and speech evaluations throughout childhood.

Vav Proteins in Development of the Brain: A Potential Relationship to the Pathogenesis of Congenital Zika Syndrome?

Zika virus (ZIKV) infection during pregnancy can result in a significant impact on the brain and eye of the developing fetus, termed congenital zika syndrome (CZS). At a morphological level, the main serious presentations of CZS are microcephaly and retinal scarring. At a cellular level, many cell types of the brain may be involved, but primarily neuronal progenitor cells (NPC) and developing neurons. Vav proteins have guanine exchange activity in converting GDP to GTP on proteins such as Rac1, Cdc42 and RhoA to stimulate intracellular signaling pathways. These signaling pathways are known to play important roles in maintaining the polarity and self-renewal of NPC pools by coordinating the formation of adherens junctions with cytoskeletal rearrangements. In developing neurons, these same pathways are adopted to control the formation and growth of neurites and mediate axonal guidance and targeting in the brain and retina. This review describes the role of Vavs in these processes and highlights the points of potential ZIKV interaction, such as (i) the binding and entry of ZIKV in cells via TAM receptors, which may activate Vav/Rac/RhoA signaling; (ii) the functional convergence of ZIKV NS2A with Vav in modulating adherens junctions; (iii) ZIKV NS4A/4B protein effects on PI3K/AKT in a regulatory loop via PPI3 to influence Vav/Rac1 signaling in neurite outgrowth; and (iv) the induction of SOCS1 and USP9X following ZIKV infection to regulate Vav protein degradation or activation, respectively, and impact Vav/Rac/RhoA signaling in NPC and neurons. Experiments to define these interactions will further our understanding of the molecular basis of CZS and potentially other developmental disorders stemming from in utero infections. Additionally, Vav/Rac/RhoA signaling pathways may present tractable targets for therapeutic intervention or molecular rationale for disease severity in CZS.

Association between Maternal Non-Coding Interferon-λ Polymorphisms and Congenital Zika Syndrome in a Cohort from Brazilian Northeast

Congenital Zika syndrome (CZS) is characterized by a diverse group of congenital malformations induced by ZIKV infection during pregnancy. Type III interferons have been associated with placental immunity against ZIKV and restriction of vertical transmission in mice, and non-coding single-nucleotide polymorphisms (SNPs) on these genes are well known to influence susceptibility to other viral infections. However, their effect on ZIKV pathogenesis has not yet been explored. To investigate whether maternal non-coding SNPs at IFNL genes are associated with CZS, 52 women infected with ZIKV during pregnancy were enrolled in a case-control association study. A total of 28 women were classified as cases and 24 as controls based on the presence or absence of CZS in their infants, and seven Interferon-λ non-coding SNPs (rs12980275, rs8099917, rs4803217, rs4803219, rs8119886, rs368234815, rs12979860) were genotyped. The results of logistic regression analyses show an association between the G allele at rs8099917 and increased susceptibility to CZS under a log-additive model (adjustedOR = 2.80; 95%CI = 1.14-6.91; p = 0.02), after adjustment for trimester of infection and genetic ancestry. These results provide evidence of an association between Interferon-λ SNPs and CZS, suggesting rs8099917 as a promising candidate for further studies on larger cohorts.

Clinical and neurodevelopmental outcomes based on brain imaging studies in a Colombian cohort of children with probable antenatal Zika virus exposure

BACKGROUND

Our aim was to describe the neuroimaging and clinical evaluations of children with antenatal Zika-virus (ZIKV) exposure.

METHODS

The Colombian National Institute of Health performed serial clinical evaluations of children with probable antenatal ZIKV exposure (i.e., born to ZIKV symptomatic mothers or born with birth defects compatible with ZIKV infection, regardless of laboratory results) over 2 years that included head circumference (HC), eye examination, and neurodevelopmental assessments. Clinical neuroimaging studies (head computed tomography and/or brain magnetic resonance imaging) were analyzed for abnormalities, two-dimensional measurements were made of the right and left frontal and occipital cortical thickness. Two abnormal patterns were defined: Pattern 1 (sum of four areas of cortex <6 cm) and Pattern 2 (sum of four areas of cortex ≥6 cm and < 10 cm).

RESULTS

Thirty-one children had a neuroimaging study; in 24, cortical thickness was measured. The median age at the first visit was 8 (range: 6-9) months and 22 (range: 19-42) months at the last evaluation. In the 24 cases with cortical measurements, three were normal, 12 were in Pattern 1, and nine were in Pattern 2. Children within Pattern 1 had lower mean HC at birth and in follow-up (both p < .05) and a higher frequency of structural eye abnormalities (p < .01). A trend towards poorer neuromotor development was seen in Pattern 1, although not statistically significant (p = .06).

CONCLUSION

Brain imaging classification based on cortical measurements correlate with ophthalmologic abnormalities and HC. Cortical thickness may be a marker for clinical outcomes in children with congenital ZIKV infection.

Zika Virus and Neuropathogenesis: The Unanswered Question of Which Strain Is More Prone to Causing Microcephaly and Other Neurological Defects

Despite being perceived to be a relatively innocuous pathogen during its circulation in Africa in the 20th century, consequent outbreaks in French Polynesia and Latin America revealed the Zika virus (ZIKV) to be capable of causing severe neurological defects. Foetuses infected with the virus during pregnancy developed a range of pathologies including microcephaly, cerebral calcifications and macular scarring. These are now collectively known as Congenital Zika syndrome (CZS). It has been established that the neuropathogenesis of ZIKV results from infection of neural progenitor cells in the developing cerebral cortex. Following this, two main hypotheses have emerged: the virus causes either apoptosis or premature differentiation of neural progenitor cells, reducing the final number of mature neurons in the cerebral cortex. This review describes the cellular processes which could potentially cause virus induced apoptosis or premature differentiation, leading to speculation that a combination of the two may be responsible for the pathologies associated with ZIKV. The review also discusses which specific lineages of the ZIKV can employ these mechanisms. It has been unclear in the past whether the virus evolved its neurotropic capability following circulation in Africa, or if the virus has always caused microcephaly but public health surveillance in Africa had failed to detect it. Understanding the true neuropathogenesis of ZIKV is key to being prepared for further outbreaks in the future, and it will also provide insight into how neurotropic viruses can cause profound and life-long neurological defects.

Neuroimaging in Children Born With Congenital Zika Syndrome: A Cohort Study

BACKGROUND AND PURPOSE

Neuroimaging findings have been associated with adverse neurologic outcomes in children with congenital Zika virus infection. Our purpose is to describe the brain magnetic resonance imaging (MRI) of children around 3 years of age, born with congenital Zika syndrome.

METHODS

This cohort study followed 62 children born with congenital Zika syndrome who had head computed tomography (CT) performed during the first months of life. All these children had clinical, neuroimaging, and serological confirmation of congenital Zika. Around 3 years of age, these children received a brain MRI.

RESULTS

In 35 children, we could perform an MRI. All these children had severe impairment in neuromotor development. In general, the examinations showed the same alterations of the CT examinations: delayed myelination (82.8%), intracranial calcification (71.4%) although with decreased intensity and size as compared with previously CT examinations, ventriculomegaly (91.4%), cerebellar hypoplasia (68.5%), and cortical development abnormalities (85.8%).

CONCLUSION

The serious brain alterations observed through head CT examinations in children born with congenital Zika syndrome continued to be detected through an MRI examination carried out at around 3 years of age. This indicates a poor prognosis for these children who had a severe neuromotor development delay.

Zika virus infection in pregnant women and their children: A review

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) transmitted primarily by Aedes mosquitoes. ZIKV can be transmitted to humans by non-vector borne mechanisms such as sexual intercourse, maternal-foetal transmission or blood transfusion. In 2015, ZIKV emerged in the Americas, and spread to 87 countries and territories with autochthonous transmission, distributed across four of the six WHO regions. Most ZIKV infections in pregnancy are asymptomatic, but mother to child transmission of the virus can occur in 20 to 30% of cases and cause severe foetal and child defects. Children exposed to ZIKV while in utero might develop a pattern of structural anomalies and functional disabilities secondary to central nervous system damage, known as congenital Zika syndrome, and whose most common clinical feature is microcephaly. Normocephalic children born to mothers with ZIKV infection in pregnancy, and with no observable Zika-associated birth defects, may also present with later neurodevelopmental delay or post-natal microcephaly. Screening and detection of ZIKV infection in pregnancy is essential, because most women with ZIKV infection are asymptomatic and clinical manifestations are non-specific. However, the diagnosis of ZIKV infection poses multiple challenges due to limited resources and scarce laboratory capabilities in most affected areas, the narrow window of time that the virus persists in the bloodstream, the large proportion of asymptomatic infections, and the cross-reactivity with other flaviviruses such as Dengue virus (DENV). Molecular methods (RT-PCR) are the most reliable tool to confirm ZIKV infection, as serodiagnosis requires confirmation with neutralization tests in case of inconclusive or positive serology results. Prenatal ultrasound assessment is essential for monitoring foetal development and early detection of possible severe anomalies. A mid- and long-term follow-up of children exposed to ZIKV while in utero is necessary to promptly detect clinical manifestations of possible neurological impairment. Tweetable abstract: Zika virus infection during pregnancy is a cause of pregnancy loss and disability in children. Protection against mosquito bites, access to sexual and reproductive health services, prompt screening and detection of ZIKV infection in pregnancy, and prenatal ultrasound monitoring are key control strategies whilst a vaccine is not available.

The Term Newborn: Congenital Infections

Maternal pathogens can be transmitted to the fetus resulting in congenital infection with sequelae ranging from asymptomatic infection to severe debilitating disease and still birth. The TORCH pneumonic (toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus) is used widely, but it provides a limited description of the expanding list of pathogens associated with congenital infection. This article focuses on the evaluation and management of infants with common congenital infections such as cytomegalovirus, and infections that warrant early diagnosis and treatment to prevent serious complications, such as toxoplasmosis, human immunodeficiency virus, and syphilis. Zika virus and Chagas disease remain uncommon.

Neurodevelopment in Children Exposed to Zika Virus: What Are the Consequences for Children Who Do Not Present with Microcephaly at Birth?

The relation of Zika virus (ZIKV) with microcephaly is well established. However, knowledge is lacking on later developmental outcomes in children with evidence of maternal ZIKV infection during pregnancy born without microcephaly. The objective of this analysis is to investigate the impact of prenatal exposure to ZIKV on neuropsychomotor development in children without microcephaly. We evaluated 274 children including 235 ZIKV exposed and 39 controls using the Bayley-III Scales of Infant and Toddler Development (BSIDIII) and neurological examination. We observed a difference in cognition with a borderline p-value (p = 0.052): 9.4% of exposed children and none of the unexposed control group had mild to moderate delays. The prevalence of delays in the language and motor domains did not differ significantly between ZIKV-exposed and unexposed children (language: 12.3% versus 12.8%; motor: 4.7% versus 2.6%). Notably, neurological examination results were predictive of neurodevelopmental delays in the BSIDIII assessments for exposed children: 46.7% of children with abnormalities on clinical neurological examination presented with delay in contrast to 17.8% among exposed children without apparent neurological abnormalities (p = 0.001). Overall, our findings suggest that relative to their unexposed peers, ZIKV-exposed children without microcephaly are not at considerably increased risk of neurodevelopmental impairment in the first 42 months of life, although a small group of children demonstrated higher frequencies of cognitive delay. It is important to highlight that in the group of exposed children, an abnormal neuroclinical examination may be a predictor of developmental delay. The article contributes to practical guidance and advances our knowledge about congenital Zika.

Cranial US in Infants Exposed to Zika Virus: The NATZIG Cohort

Background Studies addressing neuroimaging findings as primary outcomes of congenital Zika virus infection are variable regarding inclusion criteria and confirmatory laboratory testing. Purpose To investigate cranial US signs of prenatal Zika virus exposure and to describe frequencies of cranial US findings in infants exposed to Zika virus compared to those in control infants. Materials and Methods In this single-center prospective cohort study, participants were enrolled during the December 2015-July 2016 outbreak of Zika virus infection in southeast Brazil (Natural History of Zika Virus Infection in Gestation cohort). Eligibility criteria were available cranial US and laboratory findings of maternal Zika virus infection during pregnancy confirmed with RNA polymerase chain reaction testing (ie, Zika virus-exposed infants). The control group was derived from the Zika in Infants and Pregnancy cohort and consisted of infants born to asymptomatic pregnant women who tested negative for Zika virus infection during pregnancy. Two radiologists who were blinded to the maternal Zika virus infection status independently reviewed cranial US scans from both groups and categorized them as normal findings, Zika virus-like pattern, or mild findings. Associations between cranial US findings and prenatal Zika virus exposure were assessed with univariable analysis. Results Two hundred twenty Zika virus-exposed infants (mean age, 53.3 days ± 71.1 [standard deviation]; 113 boys) and born to 219 mothers infected with Zika virus were included in this study and compared with 170 control infants (mean age, 45.6 days ± 45.8; 102 boys). Eleven of the 220 Zika virus-exposed infants (5%), but no control infants, had a Zika virus-like pattern at cranial US. No difference in frequency of mild findings was observed between the groups (50 of 220 infants [23%] vs 44 of 170 infants [26%], respectively; P = .35). The mild finding of lenticulostriate vasculopathy, however, was nine times more frequent in Zika virus-exposed infants (12 of 220 infants, 6%) than in control infants (one of 170 infants, 1%) (P = .01). Conclusion Lenticulostriate vasculopathy was more common after prenatal exposure to Zika virus, even in infants with normal head size, despite otherwise overall similar frequency of mild cranial US findings in Zika virus-exposed infants and in control infants. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Benson in this issue.

Causes of Phenotypic Variability and Disabilities after Prenatal Viral Infections

Prenatal viral infection can lead to a spectrum of neurodevelopmental disabilities or fetal demise. These can include microencephaly, global developmental delay, intellectual disability, refractory epilepsy, deafness, retinal defects, and cortical-visual impairment. Each of these clinical conditions can occur on a semi-quantitative to continuous spectrum, from mild to severe disease, and often as a collective of phenotypes. Such serious outcomes result from viruses’ overlapping neuropathology and hosts’ common neuronal and gene regulatory response to infections. The etiology of variability in clinical outcomes is not yet clear, but it may be related to viral, host, vector, and/or environmental risk and protective factors that likely interact in multiple ways. In this perspective of the literature, we work toward understanding the causes of phenotypic variability after prenatal viral infections by highlighting key aspects of the viral lifecycle that can affect human disease, with special attention to the 2015 Zika pandemic. Therefore, this work offers important insights into how viral infections and environmental teratogens affect the prenatal brain, toward our ultimate goal of preventing neurodevelopmental disabilities.

Is the ZIKV Congenital Syndrome and Microcephaly Due to Syndemism with Latent Virus Coinfection?

The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.

Zika virus NS3 protease induces bone morphogenetic protein-dependent brain calcification in human fetuses

The most frequent fetal birth defect associated with prenatal Zika virus (ZIKV) infection is brain calcification, which in turn may potentially affect neurological development in infants. Understanding the mechanism could inform the development of potential therapies against prenatal ZIKV brain calcification. In perivascular cells, bone morphogenetic protein (BMP) is an osteogenic factor that undergoes maturation to activate osteogenesis and calcification. Here, we show that ZIKV infection of cultivated primary human brain pericytes triggers BMP2 maturation, leading to osteogenic gene expression and calcification. We observed extensive calcification near ZIKV⁺ pericytes of fetal human brain specimens and in vertically transmitted ZIKV⁺ human signal transducer and activator of transcription 2-knockin mouse pup brains. ZIKV infection of primary pericytes stimulated BMP2 maturation, inducing osteogenic gene expression and calcification that were completely blocked by anti-BMP2/4 neutralizing antibody. Not only did ZIKV NS3 expression alone induce BMP2 maturation, osteogenic gene expression and calcification, but purified NS3 protease also effectively cleaved pro-BMP2 in vitro to generate biologically active mature BMP2. These findings highlight ZIKV-induced calcification where the NS3 protease subverts the BMP2-mediated osteogenic signalling pathway to trigger brain calcification.

The Neurobiology of Zika Virus: New Models, New Challenges

The Zika virus (ZIKV) attracted attention due to one striking characteristic: the ability to cross the placental barrier and infect the fetus, possibly causing severe neurodevelopmental disruptions included in the Congenital Zika Syndrome (CZS). Few years after the epidemic, the CZS incidence has begun to decline. However, how ZIKV causes a diversity of outcomes is far from being understood. This is probably driven by a chain of complex events that relies on the interaction between ZIKV and environmental and physiological variables. In this review, we address open questions that might lead to an ill-defined diagnosis of CZS. This inaccuracy underestimates a large spectrum of apparent normocephalic cases that remain underdiagnosed, comprising several subtle brain abnormalities frequently masked by a normal head circumference. Therefore, new models using neuroimaging and artificial intelligence are needed to improve our understanding of the neurobiology of ZIKV and its true impact in neurodevelopment.

Zika virus infection in pregnant travellers and impact on childhood neurodevelopment in the first two years of life: A prospective observational study

BACKGROUND

The emergence of Zika virus (ZIKV) represents a threat with consequences on maternal and children's health. We aimed to assess the clinical and epidemiological characteristics of pregnant women returning from ZIKV affected areas, and the effects of maternal ZIKV infection on birth outcomes and children's health.

METHODS

This was a hospital-based prospective observational study conducted at the Hospital Clínic of Barcelona and Hospital Sant Joan de Déu, Barcelona, Spain, from January 2016 to February 2020.

RESULTS

One hundred and ninety-five pregnant women who had travelled to ZIKV affected areas during pregnancy were recruited. Four women (2.1%) had a confirmed ZIKV infection, 40 women (20.5%) a probable infection, and 151 (77.4%) were negative for ZIKV. Among the ZIKV confirmed cases, a pregnant woman suffered a miscarriage, highly plausible to be associated with ZIKV infection. Brain cysts and microcalcifications were detected in 7% of fetuses or infants from women with confirmed or probable ZIKV infection. Neurodevelopmental delay in the language function was found in 33.3% out of the 21 children evaluated.

CONCLUSIONS

These findings contribute to the understanding of ZIKV prevalence estimates, and the impact of maternal ZIKV infection on pregnancy outcomes and children's health. Results highlight the importance of long-term surveillance in pregnant travellers and their children.

Zika Virus Neutralizing Antibody Kinetics in Antenatally Exposed Infants

BACKGROUND

Zika virus (ZIKV) is associated with severe congenital abnormalities and laboratory diagnosis of antenatal infection is difficult. Here we evaluated ZIKV neutralizing antibody (Nab) kinetics in infants born to mothers with PCR-confirmed ZIKV infection during pregnancy.

METHODS

Neonates (n=98) had serum specimens tested repeatedly for ZIKV Nab over the first two years of life using virus neutralization test (VNT). ZIKV neonatal infection was confirmed by RT-PCR in blood or urine and/or presence of ZIKV IgM antibodies, and results were correlated with infant clinical features.

RESULTS

Postnatal laboratory evidence of ZIKV vertical transmission was obtained for 60.2% of children, while 32.7% exhibited clinical abnormalities. Congenital abnormalities were found in 37.3% of children with confirmed ZIKV infection and 31.0% of children without confirmed infection (p=0.734). All but one child displayed a physiologic decline in ZIKV Nab, reflecting maternal antibody decay, despite an early ZIKV-IgM response in 1/3 of infants.

CONCLUSIONS

Infants with antenatal ZIKV exposure do not develop ZIKV Nab despite an early IgM response. Therefore, ZIKV VNT in children is not useful for diagnosis of congenital infection. In light of these findings, it remains to be determined if children infected in utero are potentially susceptible to reinfection.

Time to Evaluate the Clinical Repercussions of Zika Virus Vertical Transmission? A Systematic Review

Background: Vertical transmission of Zika Virus (ZIKV) can be associated with several clinical features in newborn infants. The goal of the present review was to analyze the current state of knowledge regarding clinical repercussions following perinatal exposure to ZIKV in children up to 3 years of age. Methods: A systematic review of published studies was carried out, without the restriction of language or date of publication, identified in the databases PubMed, Virtual Health Library (BVS), Scopus, and Web of Science and the catalog for CAPES theses and dissertations. According to the proposed flowchart, the bibliographic search resulted in 1,563 papers. Of these, according to the eligibility criteria, 70 were selected for systematic review; all were published between 2016 and 2021. Results: Regarding clinical findings, 19 papers evaluated clinical imaging alterations, 21 ophthalmic manifestations, and 39 evaluated the central nervous system; of these, 15 analyzed neuro-psychomotor development. The remainder evaluated audiological (n = 14), nutritional (n = 14), orthopedic (n = 7), cardiorespiratory (n = 5), genitourinary (n = 3) or endocrinological (n = 1) manifestations. Conclusion: It is critical for studies to continue monitoring children with antenatal ZIKV exposure as they grow, given the unknown long-term repercussions of ZIKV and the recognized postnatal complications of this infection during pregnancy. Broader descriptions of observed clinical findings are also important in order to characterize the entire spectrum of disease in children. Systematic Review Registration: PROSPERO REGISTER: CRD42020205947.

Congenital Zika syndrome: A systematic review

BACKGROUND

The signs and symptoms of Zika virus infection are usually mild and self-limited. However, the disease has been linked to neurological complications such as Guillain-Barré syndrome and peripheral nerve involvement, and also to abortion and fetal deaths due to vertical transmission, resulting in various congenital malformations in newborns, including microcephaly. This review aimed to describe the o signs and symptoms that characterize the congenital Zika syndrome.

METHODS AND FINDINGS

A systematic review was performed with a protocol and described according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The search strategy yielded 2,048 studies. After the exclusion of duplicates and application of inclusion criteria, 46 studies were included. The main signs and symptoms associated with the congenital Zika syndrome were microcephaly, parenchymal or cerebellar calcifications, ventriculomegaly, central nervous system hypoplasia or atrophy, arthrogryposis, ocular findings in the posterior and anterior segments, abnormal visual function and low birthweight for gestational age.

CONCLUSIONS

Zika virus infection during pregnancy can cause a series of changes in the growth and development of children, while impacting the healthcare system due to the severity of cases. Our findings outline the disease profile in newborns and infants and may contribute to the development and updating of more specific clinical protocols.

Plaque Reduction Neutralization Test (PRNT) in the Congenital Zika Syndrome: Positivity and Associations with Laboratory, Clinical, and Imaging Characteristics

The short duration of viremia, low blood viral load, inaccessibility to timely specific diagnostic tests, and cross-reactions with other flaviviruses have hindered laboratory confirmation of Congenital Zika Syndrome (CZS). This study analyzes the positivity of the plaque reduction neutralization test (PRNT) in children with clinical or imaging characteristics of CZS and its association with laboratory, clinical, and imaging characteristics. The 94 clinical cases of CZS submitted to the ZIKV PRNT₉₀ test were followed from 2016 to 2018. The mean age of children at PRNT₉₀ collection was 22 ± 6 months Standard Deviation. The ZIKV PRNT₉₀ was positive (titer ≥ 10) in 40 (42.5%) children. ZIKV PRNT₉₀ positivity was associated with severe microcephaly in newborns (p = 0.016), lower head circumference z-score at birth (p = 0.043) and 24 months of age (p = 0.031), and severe reduction of the cerebral parenchyma volume (p = 0.021), expressing greater disease severity. Negative PRNT₉₀ in children with characteristic signs of CZS may be due to false-negative results, indicating that the diagnosis of CZS should be primarily syndromic.

Impact of Zika Virus Infection on Human Neural Stem Cell MicroRNA Signatures

Zika virus (ZIKV) is a mosquito-borne virus, which can cause brain abnormalities in newborns, including microcephaly. MicroRNAs (miRNAs) are small non-coding RNAs, which post- transcriptionally regulate gene expression. They are involved in various processes including neurological development and host responses to viral infection, but their potential role in ZIKV pathogenesis remains poorly understood. MiRNAs can be incorporated into extracellular vesicles (EVs) and mediate cell-to-cell communication. While it is well known that in viral infections EVs carrying miRNAs can play a crucial role in disease pathogenesis, ZIKV effects on EV-delivered miRNAs and their contribution to ZIKV pathogenesis have not been elucidated. In the present study, we profiled intracellular and EV-derived miRNAs by next generation sequencing and analyzed the host mRNA transcriptome of neural stem cells during infection with ZIKV Uganda and French Polynesia strains. We identified numerous miRNAs, including miR-4792, which were dysregulated at the intracellular level and had altered levels in EVs during ZIKV infection. Integrated analyses of differentially expressed genes and miRNAs showed that ZIKV infection had an impact on processes associated with neurodevelopment and oxidative stress. Our results provide insights into the roles of intracellular and EV-associated host miRNAs in ZIKV pathogenesis.

Pediatric neurodevelopment by prenatal Zika virus exposure: a cross-sectional study of the Microcephaly Epidemic Research Group Cohort

Background

The implications of congenital Zika Virus (ZIKV) infections for pediatric neurodevelopment and behavior remain inadequately studied. The aim of this study is to investigate patterns of neurodevelopment and behavior in groups of children with differening severities of ZIKV-related microcephaly and children with prenatal ZIKV exposure in the absence of microcephaly.

Methods

We conducted a cross-sectional study, nested in a cohort, of 274 children (aged 10–45 months) who were born during the peak and decline of the microcephaly epidemic in Northeast Brazil. Participants were evaluated between February 2017 and August 2019 at two tertiary care hospitals in Recife, Pernambuco, Brazil. We analyzed the children in four groups assigned based on clinical and laboratory criteria: Group 1 had severe microcephaly; Group 2 had moderate microcephaly; Group 3 had prenatal ZIKVexposure confirmed by maternal RT-PCR testing but no microcephaly; and Group 4 was a neurotypical control group. Groups were evaluated clinically for neurological abnormalities and compared using the Survey of Wellbeing of Young Children (SWYC), a neurodevelopment and behavior screening instrument validated for use in Brazil. Children with severe delays underwent further evaluation with an adapted version of the SWYC.

Results

Based on the SWYC screening, we observed differences between the groups for developmental milestones but not behavior. Among the 114 children with severe microcephaly of whom 98.2% presented with neurological abnormalities, 99.1% were ‘at risk of development delay’ according to the SWYC instrument. Among the 20 children with moderate microcephaly of whom 60% presented with neurological abnormalities, 65% were ‘at risk of development delay’. For children without microcephaly, the percentages found to be ‘at risk of developmental delay’ were markedly lower and did not differ by prenatal ZIKV exposure status: Group 3 (N = 94), 13.8%; Group 4 (N = 46), 21.7%.

Conclusions

Among children with prenatal ZIKV exposure, we found a gradient of risk of development delay according to head circumference. Children with severe microcephaly were at highest risk for delays, while normocephalic ZIKV-exposed children had similar risks to unexposed control children. We propose that ZIKV-exposed children should undergo first-line screening for neurodevelopment and behavior using the SWYC instrument. Early assessment and follow-up will enable at-risk children to be referred to a more comprehensive developmental evaluation and to multidisciplinary care management.

Congenital Zika syndrome: association between the gestational trimester of maternal infection, severity of brain computed tomography findings and microcephaly at birth

This study analyzed possible associations between the trimester of maternal Zika virus infection (ZIKV) in pregnancy, severity of brain computed tomography (CT) findings and the presence of microcephaly at birth in children with Congenital Zika Syndrome (CZS). It was an analytical study in a cohort of children with CZS. Symptoms of maternal infection were dichotomized into the 1^st trimester of pregnancy and other trimesters. Head circumference (HC) at birth was used to calculate the z-score. Mild microcephaly was defined as HC between 2 and ≥3 standard deviations (SD) below the mean for each gestational age and sex, and severe microcephaly when HC <3 SD below average. Brain CT images were evaluated by two radiologists and classified, according to the severity, into mild, moderate and severe. Fisher’s exact, Mann-Whitney and Kruskal-Wallis tests were used to verify the associations between variables. In 108 children, maternal infection in the 1^st trimester of pregnancy was associated with more severe brain CT abnormalities (p=0.038), greater severity of microcephaly at birth (p=0.013) and lower HC z-scores at birth (p=0.021). The severity of brain CT lesions was also associated with lower HC z-scores at birth (p<0.001). Maternal ZIKV infection during the first trimester of pregnancy proved to be an important risk factor for a more severe spectrum of CZS, as it is associated with more severe brain CT abnormalities and, consequently, with lower HC z-scores at birth.

Zika virus vertical transmission in children with confirmed antenatal exposure

We report Zika virus (ZIKV) vertical transmission in 130 infants born to PCR+ mothers at the time of the Rio de Janeiro epidemic of 2015–2016. Serum and urine collected from birth through the first year of life were tested by quantitative reverse transcriptase polymerase chain reaction (PCR) and/or IgM Zika MAC-ELISA. Four hundred and seven specimens are evaluated; 161 sera tested by PCR and IgM assays, 85 urines by PCR. Sixty-five percent of children (N = 84) are positive in at least one assay. Of 94 children tested within 3 months of age, 70% are positive. Positivity declines to 33% after 3 months. Five children are PCR+ beyond 200 days of life. Concordance between IgM and PCR results is 52%, sensitivity 65%, specificity 40% (positive PCR results as gold standard). IgM and serum PCR are 61% concordant; serum and urine PCR 55%. Most children (65%) are clinically normal. Equal numbers of children with abnormal findings (29 of 45, 64%) and normal findings (55 of 85, 65%) have positive results, p = 0.98. Earlier maternal trimester of infection is associated with positive results (p = 0.04) but not clinical disease (p = 0.98). ZIKV vertical transmission is frequent but laboratory confirmed infection is not necessarily associated with infant abnormalities.

Here, Brasil et al. investigate mother to child Zika virus (ZIKV) transmission rates in a large longitudinal cohort of pregnant ZIKV-positive women with their infants followed from the time of maternal infection through birth and onwards, finding high in utero transmission rates that do not predict clinical outcomes, suggesting follow-up of children with antenatal ZIKV exposure is necessary.

Association Between Antenatal Exposure to Zika Virus and Anatomical and Neurodevelopmental Abnormalities in Children

IMPORTANCE

Zika virus (ZIKV) is a mosquito-borne flavivirus recognized as teratogenic since the 2015 to 2016 epidemic. Antenatal ZIKV exposure causes brain anomalies, yet the full spectrum has not been delineated.

OBJECTIVE

To characterize the clinical features of ZIKV infection at a pediatric referral center in Rio de Janeiro, Brazil, among children with antenatal ZIKV exposure.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study conducted from May to July 2019 of a prospective cohort of 296 infants with antenatal ZIKV exposure followed up since December 2015 at a tertiary maternity-pediatric hospital.

EXPOSURES

Zika virus infection during pregnancy.

MAIN OUTCOMES AND MEASURES

Characterization of clinical features with anthropometric, neurologic, cardiologic, ophthalmologic, audiometric, and neuroimaging evaluations in infancy and neurodevelopmental assessments (Bayley Scales of Infant and Toddler Development, Third Edition) from 6 to 42 months of age, stratified by head circumference at birth (head circumference within the reference range, or normocephaly [NC] vs microcephaly [MC]).

RESULTS

Antenatal exposure to ZIKV was confirmed for 219 of 296 children (74.0%) referred to Instituto Fernandes Figueira with suspected ZIKV infection through positive maternal or neonatal polymerase chain reaction analysis or IgM serology results. Of these children, 110 (50.2%) were boys, ages ranged from 0 to 4 years, and 53 (24.2%) had congenital microcephaly. The anomalies observed in ZIKV-exposed children with MC or NC were failure to thrive (MC: 38 of 53 [71.7%]; NC: 73 of 143 [51.0%]), cardiac malformations (MC: 19 of 46 [41.3%]; NC: 20 of 100 [20.0%]), excess nuchal skin (MC: 16 of 22 [72.7%]; NC: 35 of 93 [37.6%]), auditory abnormalities (MC: 13 of 50 [26.0%]; NC: 14 of 141 [9.9%]), and eye abnormalities (MC: 42 of 53 [79.2%]; NC: 28 of 158 [17.7%]). Although they experienced fewer neurologic abnormalities than children born with MC, those with NC also had frequent neurologic abnormalities (109 of 160 [68.1%]), including hyperreflexia (36 of 136 [26.5%]), abnormal tone (53 of 137 [38.7%]), congenital neuromotor signs (39 of 93 [41.9%]), feeding difficulties (15 of 143 [10.5%]), and abnormal brain imaging results (44 of 150 [29.3%]). Among 112 children with NC with Bayley-III evaluations, 72 (64.3%) had average or above-average scores; 30 (26.8%) scored 1 SD below average in at least 1 domain; and 10 (8.9%) scored 2 SD below average in at least 1 domain. Among 112 children with NC, a smaller head circumference at birth was significantly associated with subsequent below-average cognitive scores (U = 499.5; z = -2.833; P = .004) and language scores (U = 235.5; z = -2.491; P = .01).

CONCLUSIONS AND RELEVANCE

Children without MC who were exposed to ZIKV in utero had a high frequency of anatomical and neurodevelopmental abnormalities. The head circumference at birth for children with NC was associated with neurocognitive development. Recognition of the wide spectrum of clinical phenotypes is critical to ensure early referral to rehabilitative interventions.

Review of neuroimaging findings in congenital Zika virus syndrome and its relation to the time of infection

BACKGROUND

Many original articles and case series have been published emphasizing the neuroimaging findings of congenital Zika virus (ZIKV) infection. The majority of these studies do not follow a neuroradiological methodology to describe malformations and brain abnormalities resulting from ZIKV infection. The cause-and-effect correlation between the gestational period of maternal infection and the severity of encephalic changes at birth has rarely been reported. A systematic literature review was conducted on the neuroimaging findings in children affected with microcephaly due to ZIKV.

METHODS

PubMed, Cochrane Library and Web of Science were searched for full-text articles published up to July 2019. Duplicate entries were removed. Two independent reviewers performed a quality assessment of all the studies included.

RESULTS

A total of 2214 publications were identified. Of these 2170 were excluded by analysis of titles and abstracts, resulting in the inclusion of only eight articles. Chi-square and Fisher's exact tests were performed with a 95% confidence interval to verify the statistically significant differences in the neuroradiological findings between the cases of ZIKV infection in the first or second trimester of gestation. The studies published so far have described image abnormalities at random, without utilizing any pre-established neuroradiological criteria, and imaging modalities with different sensitivity and accuracy have been used, which jeopardizes a reliable and adequate statistical analysis.

CONCLUSIONS

Neuroimaging abnormalities are much more prevalent and severe when the infection by ZIKV is contracted in the first or second trimester of pregnancy.