Zika-Associated Microcephaly Can Present After Birth

Researchers report on more than a dozen cases in which babies who showed signs of in-utero infection but were born without symptoms of congenital Zika syndrome went on to develop brain abnormalities. 

Nov 23, 2016
Tracy Vence

WIKIMEDIA, CDCNine baby boys and four baby girls with laboratory evidence of congenital Zika virus infection, who did not appear to have microcephaly or related neurological conditions at birth, went on to develop brain abnormalities associated with congenital Zika syndrome, researchers from Brazil and the U.S. reported today (November 22) in the Centers for Disease Control and Prevention (CDC)’s Morbidity and Mortality Weekly Report. While the babies’ at-birth head circumferences did not meet the criteria for microcephaly diagnoses, upon later neurologic and neuroimaging evaluations at health care centers in Brazil, researchers identified Zika-associated complications.

“Congenital microcephaly has been a hallmark of intrauterine infection with Zika virus,” the authors wrote in their report. “However, despite the absence of microcephaly at birth, the 13 infants in this report with laboratory evidence of Zika virus infection had brain abnormalities associated with congenital Zika syndrome, including ventriculomegaly and decreased brain volume, cortical malformations and subcortical calcifications, underscoring the importance of neuroimaging in evaluating these infants.”

Of the 13 infants studied, 11 went on to develop microcephaly, according to a CDC statement.

“This report documents that microcephaly at birth is not an essential hallmark of congenital Zika syndrome. Infants with normal HC [head circumference] at birth have brain and other abnormalities associated with congenital Zika syndrome and might develop microcephaly after birth,” the authors added in their report. “These findings demonstrate the importance of early neuroimaging for infants exposed to Zika virus prenatally and the need for comprehensive medical and developmental follow-up.”

Further reading:

Researchers Discuss Zika’s Effects on Child Development,” The Scientist, September 22, 2016

How Zika Infects Mother and Baby,” The Scientist, August 25, 2016

WHO to People in Zika-Affected Areas: Consider Delaying Pregnancy,” The Scientist, June 10, 2016

Scientists Estimate Zika-Related Microcephaly Risk,” The Scientist, May 26, 2016

Read the latest on Zika virus.