Tag Archive for: Brazil

Paradoxical outcomes for Zika-exposed tots

In the midst of an unprecedented Zika crisis in Brazil, there were a few flickers of hope: Some babies appeared to be normal at birth, free of devastating birth defects that affected other Brazilian children exposed to the virus in utero.

In the midst of an unprecedented Zika crisis in Brazil, there were a few flickers of hope: Some babies appeared to be normal at birth, free of devastating birth defects that affected other Brazilian children exposed to the virus in utero. But according to a study published online July 8, 2019, in Nature Medicine and an accompanying commentary co-written by a Children’s National clinician-researcher, the reality for Zika-exposed infants is much more complicated.

Study authors led by Karin Nielsen-Saines at David Geffen UCLA School of Medicine followed 216 infants in Rio de Janeiro who had been exposed to the Zika virus during pregnancy, performing neurodevelopmental testing when the babies ranged in age from 7 to 32 months. These infants’ mothers had had Zika-related symptoms themselves, including rash.

Although many children had normal assessments, 29% scored below average in at least one domain of neurological development, including cognitive performance, fine and gross motor skills and expressive language, Sarah B. Mulkey, M.D., Ph.D., and a colleague write in a companion commentary published online by Nature Medicine July 29, 2019.

The study authors found progressively higher risks for developmental, hearing and eye abnormality depending on how early the pregnancy was at the time the infants were exposed. Because Zika virus has an affinity for immature neurons, even babies who were not born with microcephaly remained at continued risk for suffering abnormalities.

Of note, 24 of 49 (49%) infants who had abnormalities at birth went on to have normal test results in the second or third year of life. By contrast, 17 of 68 infants (25%) who had normal assessments at birth had below-average developmental testing or had abnormalities in hearing or vision by age 32 months.

“This work follows babies who were born in 2015 and 2016. It’s heartening that some babies born with abnormalities tested in the normal range later in life, though it’s unclear whether any specific interventions help to deliver these positive findings,” says Dr. Mulkey, a fetal–neonatal neurologist in the Division of Fetal and Transitional Medicine at Children’s National in Washington, D.C. “And it’s quite sobering that babies who appeared normal at birth went on to develop abnormalities due to that early Zika exposure.”

It’s unclear how closely the findings apply to the vast majority of U.S. women whose Zika infections were asymptomatic.

“This study adds to the growing body of research that argues in favor of ongoing follow-up for Zika-exposed children, even if their neurologic exams were reassuring at birth,” Dr. Mulkey adds. “As Zika-exposed children approach school age, it’s critical to better characterize the potential implications for the education system and public health.”

In addition to Dr. Mulkey, the perspective’s senior author, William J. Muller, Northwestern University, was the commentary’s lead author.

zika virus

Neuroimaging essential for Zika cases

zika virus

About three years ago, Zika virus emerged as a newly recognized congenital infection, and a growing body of research indicates the damage it causes differs from other infections that occur in utero.

Seventy-one of 110 Brazilian infants at the highest risk for experiencing problems due to exposure to the Zika virus in the womb experienced a wide spectrum of brain abnormalities, including calcifications and malformations in cortical development, according to a study published July 31, 2019 in JAMA Network Open.

The infants were born at the height of Brazil’s Zika epidemic, a few months after the nation declared a national public health emergency. Already, many of the infants had been classified as having the severe form of congenital Zika syndrome, and many had microcephaly, fetal brain disruption sequence, arthrogryposis and abnormal neurologic exams at birth.

These 110 infants “represented a group of ZIKV-exposed infants who would be expected to have a high burden of neuroimaging abnormalities, which is a difference from other reported cohorts,” Sarah B. Mulkey, M.D., Ph.D., writes in an invited commentary published in JAMA Network Open that accompanies the Rio de Janeiro study. “Fortunately, many ZIKV-exposed infants do not have abnormal brain findings or a clinical phenotype associated with congenital Zika syndrome,” adds Dr. Mulkey, a fetal–neonatal neurologist in the Division of Fetal and Transitional Medicine at Children’s National in Washington, D.C.

Indeed, a retrospective cohort of 82 women exposed to Zika during their pregnancies led by a research team at Children’s National found only three pregnancies were complicated by severe fetal brain abnormalities. Compared with the 65% abnormal computed tomography (CT) or magnetic resonance imaging (MRI) findings in the new Brazilian study, about 1 in 10 (10%) of babies born to women living in the continental U.S. with confirmed Zika infections during pregnancy had Zika-associated birth defects, according to the Centers for Disease Control and Prevention.

“There appears to be a spectrum of brain imaging abnormalities in ZIKV-exposed infants, including mild, nonspecific changes seen at cranial US [ultrasound], such as lenticulostriate vasculopathy and germinolytic cysts, to more significant brain abnormalities, such as subcortical calcifications, ventriculomegaly and, in its most severe form, thin cortical mantle and fetal brain disruption sequence,” Dr. Mulkey writes.

About three years ago, Zika virus emerged as a newly recognized congenital infection, and a growing body of research indicates the damage it causes differs from other infections that occur in utero. Unlike congenital cytomegalovirus infection, cerebral calcifications associated with Zika are typically subcortical, Dr. Mulkey indicates. What’s more, fetal brain disruption sequence seen in Zika-exposed infants is unusual for other infections that can cause microcephaly.

“Centered on the findings of Pool, et al, and others, early neuroimaging remains one of the most valuable investigations of the Zika-exposed infant,” Dr. Mulkey writes, including infants who are not diagnosed with congenital Zika syndrome.  She recommends:

  • Cranial ultrasound as the first-line imaging option for infants, if available, combined with neurologic and ophthalmologic exams, and brainstem auditory evoked potentials
  • Zika-exposed infants with normal cranial ultrasounds do not need additional imaging unless they experience a developmental disturbance
  • Zika-exposed infants with abnormal cranial ultrasounds should undergo further neuroimaging with low-dose cranial CT or brain MRI.