Neurodevelopmental assessment of normocephalic children born to Zika virus exposed and unexposed pregnant people

A Review of the Recent Epidemiology of Zika Virus Infection

Zika virus (ZIKV) is a flavivirus transmitted primarily by the bite of infected Aedes species mosquitoes. Although typically asymptomatic or causing mild symptoms and infrequent neurological disease in older children and adults, infection during pregnancy can result in severe congenital malformations and neurodevelopmental deficits. We conducted a review of published literature and official data sources to describe recent Zika epidemiological trends, building on WHO updates posted in 2019 and 2022. Globally, cases declined after the height of ZIKV transmission in the Americas in 2015-2016; however, transmission continues across multiple regions, with intermittent outbreaks reported. As of December 2023, there is documented evidence of current or prior autochthonous mosquito-borne ZIKV transmission in 92 countries and territories; most recently, Guinea, Mali, and Sri Lanka were included on the basis of recent or retrospective testing of specimens collected during surveillance activities or studies. The abundance of asymptomatic and mild infections and limited diagnostic testing suggest that transmission in many locations likely remains underrecognized. Public health authorities, clinicians, communities at risk, and travelers should remain alert to the possibility of ZIKV transmission and implement measures to limit the risk of infection with ZIKV and other Aedes-borne arboviruses. To strengthen surveillance for ZIKV infections and congenital disease, targeted surveillance using clear case definitions and epidemiologically appropriate laboratory testing algorithms should be applied.

Late-onset hearing loss was not observed among preschool- aged children with prenatal Zika virus exposure: An analysis of the Microcephaly Epidemic Research Group Pediatric Cohort (2015-2019)

Zika virus (ZIKV) infection during pregnancy can lead to Congenital Zika Syndrome (CZS), with significant impacts on early childhood development. This study aimed to analyze the natural history of hearing loss in children with CZS during their first four years of life. Data were collected from the Microcephaly Epidemic Research Group Pediatric Cohort in Pernambuco, Brazil. We investigated whether children with prenatal ZIKV exposure could develop late-onset hearing loss and whether those with preserved auditory thresholds at birth might exhibit deficits in functional hearing or primary language development.The study included children with suspected or confirmed prenatal ZIKV exposure who had normal neonatal hearing screenings. Follow-up assessments included auditory brainstem response testing and behavioral observational audiometry. Children were evaluated every six months up to 24 months of age and annually thereafter until 48 months. Results indicated that late-onset sensorineural hearing loss (SNHL) was not observed in children with prenatal ZIKV exposure and normal neonatal hearing screening. The hearing losses identified were transient and typically related to middle ear effusion. Therefore, our findings reinforce that congenital SNHL associated with ZIKV exposure predominantly manifests at birth, with no evidence supporting its late onset in the first years of life.

School-age child neurodevelopment following antenatal Zika virus exposure

BACKGROUND

Children exposed antenatally to Zika virus (ZIKV) during the 2015-2016 epidemic are now in school; little is known about their neurodevelopment at this age. The objective was to evaluate neurodevelopment of ZIKV-exposed Colombian children compared to non-exposed controls at ages 5-6.

METHODS

In total, 48 normocephalic children with antenatal ZIKV exposure (Cases) were recruited for a longitudinal cohort study in Atlántico, Colombia. Two age-matched control groups of 118 non-ZIKV-exposed children were recruited from same communities as Cases: 63 born before ZIKV epidemic but experienced COVID-19-related school entry delays, and 55 born post-ZIKV epidemic but started school on time. Multi-domain neurodevelopment was assessed at 5-6 years using standardized measures. Standard regression and proportional odds models were used to compare outcomes. P values were adjusted using the Benjamini-Hochberg false discovery rate (FDR) (p < 0.05).

RESULTS

There were no differences in age at assessment between groups. Case Full-Scale IQ scores were lower than both control groups (p = 0.002), driven by visual reasoning (p < 0.001). Controls with school entry delay had more executive control problems and lower adaptive functioning skills than Cases and Controls without school entry delay.

CONCLUSIONS

ZIKV-exposed children have lower cognitive performance compared to controls. Early childhood experiences can affect pediatric outcomes research.

IMPACT

Normocephalic ZIKV-exposed children have lower full-scale IQ than their unexposed peers from the same communities. Normocephalic children with antenatal ZIKV exposure have differences in neurodevelopment that can impact them long-term. There is a need for continued follow-up of children with antenatal ZIKV exposure to determine long-term effects on higher-order areas of cognitive function.

Flaviviruses-Induced Neurological Sequelae

Flaviviruses, a group of single-stranded RNA viruses spread by mosquitoes or ticks, include several significant neurotropic viruses, such as West Nile virus (WNV), Japanese encephalitis virus (JEV), tick-borne encephalitis virus (TBEV), and Zika virus (ZIKV). These viruses can cause a range of neurological diseases during acute infection, from mild, flu-like symptoms to severe and fatal encephalitis. A total of 20-50% of patients who recovered from acute flavivirus infections experienced long-term cognitive issues. Here, we discuss these major neurotropic flaviviruses-induced clinical diseases in humans and the recent findings in animal models and provide insights into the underlying disease mechanisms.

Associations between the social environment and early childhood developmental outcomes of Puerto Rican children with prenatal Zika virus exposure: a cross-sectional study

BACKGROUND

Prenatal exposure to the Zika virus can lead to microcephaly and adverse developmental outcomes, even in children without evident birth defects. The social environment plays a crucial role in infant health and developmental trajectories, especially during periods of heightened brain plasticity. The study aimed to assess socioenvironmental factors as predictors of developmental outcomes of 36-month-old children exposed to Zika virus prenatally.

STUDY DESIGN

This cross-sectional study included 53 mothers and 55 children enrolled in the Pediatric Outcomes of Prenatal Zika Exposure cohort study in Puerto Rico. The study performs follow-up developmental assessments of children born to mothers with confirmed and probable Zika virus infection during pregnancy. Mothers completed socioenvironmental questionnaires (e.g., Perceived Neighborhood Scale and US Household Food Insecurity Survey). Children's developmental outcomes were assessed with the Bayley Scales of Infant and Toddler Development: Third Edition, the Ages and Stages Questionnaires: Third Edition, the Ages and Stages Questionnaire-Socioemotional: Second Edition, and the Child Adjustment and Parent Efficacy Scale.

RESULTS

Linear regression models, adjusting for a child's sex and age and maternal education, revealed that early life exposure to food insecurity and maternal pregnancy stressors were significantly associated with poorer developmental outcomes in Zika virus-exposed children at 36 months of age. Maternal resilience representation of adaptive ability was associated with the preservation of adequate developmental outcomes in children.

CONCLUSIONS

Pregnancy and early childhood are critical life periods for ensuring optimal brain development in children. While the mechanisms in the interaction of children with their environment are complex, the risk and protective factors identified in the study are modifiable through public policy and preventive initiatives. Implementation of comprehensive strategies that improve access to social support programs, educational and nutritional interventions, and mental health services during pregnancy and early childhood can enhance the developmental potential of vulnerable children.

Neurodevelopmental Outcomes of Normocephalic Colombian Children with Antenatal Zika Virus Exposure at School Entry

The long-term neurodevelopmental effects of antenatal Zika virus (ZIKV) exposure in children without congenital Zika syndrome (CZS) remain unclear, as few children have been examined to the age of school entry level. A total of 51 Colombian children with antenatal ZIKV exposure without CZS and 70 unexposed controls were evaluated at 4-5 years of age using the Behavior Rating Inventory of Executive Function (BRIEF), the Pediatric Evaluation of Disability Inventory (PEDI-CAT), the Bracken School Readiness Assessment (BSRA), and the Movement Assessment Battery for Children (MABC). The mean ages at evaluation were 5.3 and 5.2 years for cases and controls, respectively. Elevated BRIEF scores in Shift and Emotional Control may suggest lower emotional regulation in cases. A greater number of cases were reported by parents to have behavior and mood problems. BSRA and PEDI-CAT activity scores were unexpectedly higher in cases, most likely related to the COVID-19 pandemic and a delayed school entry among the controls. Although PEDI-CAT mobility scores were lower in cases, there were no differences in motor scores on the MABC. Of 40 cases with neonatal neuroimaging, neurodevelopment in 17 with mild non-specific findings was no different from 23 cases with normal neuroimaging. Normocephalic children with ZIKV exposure have positive developmental trajectories at 4-5 years of age but differ from controls in measures of emotional regulation and adaptive mobility, necessitating continued follow-up.