A study today in JAMA Pediatrics offers more evidence of how a pregnancy affected by the Zika virus can result in long-lasting effects on children, even those born healthy and with normal brain imaging.
The study followed a cohort of babies born to Zika-infected mothers during the height of the Zika epidemic in Colombia. The 70 children were born from Aug 1, 2016, to Nov 30, 2017, and were included in the study if they had normal fetal brain findings on magnetic resonance imaging (MRI) and ultrasonography, no signs of microcephaly at birth, and no clinical evidence of congenital Zika syndrome.
Normal early assessments
All infants in the study had healthy assessments at 4 months, but by 18 months of age, the children's overall social cognition scores declined, as did developmental markers for mobility. No decreases in head circumference were recorded.
"These infants were expected to have low risk for subsequent neurodevelopmental deficits, yet these deficits emerged in the first year of life and without a reduction in head circumference," the authors said.
The study also showed that 37% of the children had non-specific findings on MRI, including findings of lenticulostriate vasculopathy, germinolytic or subependymal cysts, and choroid plexus cysts. This is the first known study to describe these non-specific findings as a potential precursor to developmental delays related to Zika, the authors note.
"This study is the first to show that these nonspecific imaging findings may indicate subtle brain injury potentially associated with impaired neuromotor development," the authors said.
Possible implications for US
Though the Zika epidemic in the Americas peaked in 2016, this study suggests that thousands of children in the United States may be dealing with the long-term consequences of prenatal Zika infection—and many parents may be unaware of the continued risk of the virus.
In an accompanying commentary, Margaret Honein, MD, PhD, chief of the Birth Defects Branch at the US Centers for Disease Control and Prevention (CDC), and her CDC colleagues said the findings of this study should be a warning to the 7,400 US pregnant women with confirmed or suspected Zika infections seen in the last 4 years.
"Although between 5% and 10% of these children have received a diagnosis of serious defects of the brain or eye, including microcephaly, many of them have not undergone the recommended postnatal brain imaging and ophthalmological examinations to fully identify these health problems," Honein and her coauthors said.
Postnatal imaging on these children is very important, they added.
"The findings add to the growing evidence of the need for long-term follow-up for all children with Zika virus exposure in utero to ensure they receive the recommended clinical evaluations even when no structural defects are identified at birth; we are currently far from meeting that objective," they wrote.
Estimates vary across cohorts, but only 60% of infants in US territories and freely associated states had received postnatal neuroimaging, 36% had received an ophthalmologic evaluation, and 76% had received at least one developmental screening or assessment, the CDC scientists added.
Jan 6 JAMA Pediatrics study
Jan 6 JAMA Pediatrics commentary