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.

The Microcephaly Epidemic Research Group Paediatric Cohort (MERG-PC): A Cohort Profile.

This cohort profile aims to describe the ongoing follow-up of children in the Microcephaly Epidemic Research Group Paediatric Cohort (MERG-PC). The profile details the context and aims of the study, study population, methodology including assessments, and key results and publications to date. The children that make up MERG-PC were born in Recife or within 120 km of the city, in Pernambuco/Brazil, the epicentre of the microcephaly epidemic. MERG-PC includes children from four groups recruited at different stages of the ZIKV microcephaly epidemic in Pernambuco, i.e., the Outpatient Group (OG/n = 195), the Microcephaly Case-Control Study (MCCS/n = 80), the MERG Pregnant Women Cohort (MERG-PWC/n = 336), and the Control Group (CG/n = 100). We developed a comprehensive array of clinical, laboratory, and imaging assessments that were undertaken by a 'task force' of clinical specialists in a single day at 3, 6, 12, 18 months of age, and annually from 24 months. Children from MCCS and CG had their baseline assessment at birth and children from the other groups, at the first evaluation by the task force. The baseline cohort includes 711 children born between February 2015 and February 2019. Children's characteristics at baseline, excluding CG, were as follows: 32.6% (184/565) had microcephaly, 47% (263/559) had at least one physical abnormality, 29.5% (160/543) had at least one neurological abnormality, and 46.2% (257/556) had at least one ophthalmological abnormality. This ongoing cohort has contributed to the understanding of the congenital Zika syndrome (CZS) spectrum. The cohort has provided descriptions of paediatric neurodevelopment and early epilepsy, including EEG patterns and treatment response, and information on the frequency and characteristics of oropharyngeal dysphagia; cryptorchidism and its surgical findings; endocrine dysfunction; and adenoid hypertrophy in children with Zika-related microcephaly. The study protocols and questionnaires were shared across Brazilian states to enable harmonization across the different studies investigating microcephaly and CZS, providing the opportunity for the Zika Brazilian Cohorts Consortium to be formed, uniting all the ZIKV clinical cohorts in Brazil.

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 with arthrogryposis: retrospective case series study.

OBJECTIVE: To describe the clinical, radiological, and electromyographic features in a series of children with joint contractures (arthrogryposis) associated with congenital infection presumably caused by Zika virus. DESIGN: Retrospective case series study. SETTING: Association for Assistance of Disabled Children, Pernambuco state, Brazil. PARTICIPANTS: Seven children with arthrogryposis and a diagnosis of congenital infection presumably caused by Zika virus during the Brazilian microcephaly epidemic. MAIN OUTCOME MEASURES: Main clinical, radiological, and electromyographic findings, and likely correlation between clinical and primary neurological abnormalities. RESULTS: The brain images of all seven children were characteristic of congenital infection and arthrogryposis. Two children tested positive for IgM to Zika virus in the cerebrospinal fluid. Arthrogryposis was present in the arms and legs of six children (86%) and the legs of one child (14%). Hip radiographs showed bilateral dislocation in seven children, subluxation of the knee associated with genu valgus in three children (43%), which was bilateral in two (29%). All the children underwent high definition ultrasonography of the joints, and there was no evidence of abnormalities. Moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography (monopolar). Five of the children underwent brain computed tomography (CT) and magnetic resonance imaging (MRI) and the remaining two CT only. All presented malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. MRI of the spine in four children showed apparent thinning of the cord and reduced ventral roots. CONCLUSIONS: Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis. The arthrogryposis was unrelated to the abnormalities of the joints themselves, but was possibly of neurogenic origin, with chronic involvement of central and peripheral motor neurones leading to deformities as a result of fixed postures in utero. Based on the neurophysiological observations, we suggest two possible mechanisms: tropism of neurones, with involvement of peripheral and central motor neurones, or a relation with vascular disorders.