One third of children under three exposed to Zika in utero have neurological problems

A new study by UCLA suggests that 32% of children aged 3 and over exposed to the Zika virus during their mother's pregnancy had below average neurological development.

The study also found that less than 4% of the 216 children badessed had microcephaly, a smaller than normal head that is one of the characteristics of the disease transmitted by mosquitoes. The researchers reported that the heads of two of these children had returned to normal size over time.

The study was published in the journal Nature Medicine.

The findings, conducted by UCLA researchers with colleagues in Rio de Janeiro, Brazil, where the disease was detected for the first time, as well as in Austria and Germany, follow earlier research. This study revealed significant neurological damage demonstrated by developmental tests and neuroimaging in children under two whose mothers had been infected with Zika during their pregnancy.

"Children exposed to Zika during their mother's pregnancy must undergo an badessment of their development over time, as well as eye and hearing examinations," said Dr. Karin Nielsen-Saines, author Principal of the study, Professor of Clinical Pediatrics Division of Pediatric Infectious Diseases at David Geffen School of Medicine at UCLA and UCLA Mattel Children's Hospital. "If there is a risk of developmental delay, or if developmental delay is identified, cognitive, language and behavioral interventions can be put in place to improve outcomes for these children."

The researchers tested 146 children using the Bayley-III test, an extensive neurodevelopmental badessment that verifies linguistic, cognitive, and motor development. They used the Hammersmith Infant Neural Neurological Assessment, or HINE, a less detailed evaluation, of the other 70 children whose parents did not wish to take their children for the long Bayley-III.

The researchers found that in the Bayley-III group, 51 children tested for language, 14 tested for cognitive development, and 24 badessed for motor development scored below average.

In the HINE group, three children had abnormal results and 67 had normal results.

In addition, 10 of the 137 children who underwent an eye examination had abnormal results and 14 of the 114 children with auditory controls had hearing loss.

Two children in the study had normal head measurements at birth, but had developed microcephaly during their first year, while two others with microcephaly at the time of birth had developed a normal head circumference at the age of one year.

"This means that microcephaly is not necessarily static," said Nielsen-Saines.

The researchers did not have a control group of children not exposed to Zika, born at the same time and raised in the same environment as those known to have been exposed to Zika in utero.

"Exposure to Zika can be a very difficult condition to diagnose retrospectively, so we can not exclude an undiagnosed Zika infection in a control group of children enrolled at the same time," said Nielsen-Saines. . "Neurodevelopmental tests must be performed simultaneously in similar populations with the same background."

Nielsen-Saines noted that appropriate long-term follow-up of children whose mothers had contracted Zika infection during pregnancy was necessary.

"These children require special attention and constant monitoring, so that quick interventions to improve their development can be provided if needed," she said.