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Brazilians publish largest-ever study on the after-effects of Zika
Researcher Maria Elizabeth Lopes Moreira, from the Fernandes Figueira National Institute of Health for Women, Children, and Adolescents, which is part of the ZBC-Consortium, spoke to Agência Brasil on Tuesday (Jan. 6) about the importance of the article. “No previous study has been published with this number of children,” she noted.
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The data were investigated in order to describe cases, standardize the information, and define the spectrum of microcephaly caused by this virus.
Maria Elizabeth recalled that the highest incidence of Zika-related microcephaly in the world occurred in Brazil, which experienced an epidemic of the disease from 2015 to 2016.
In her view, the most significant result of the study was the definition of the morphology of microcephaly – i.e. how it differed from microcephaly caused by other factors.
What makes the study special, she argues, is that the researchers took the original database and sorted through all the cases. “The primary data from different studies in Brazil were examined, in addition to the large number of cases,” she said.
Until then, the characterization of congenital Zika syndrome was based on case series and studies with few participants, or on individual studies.
“The relatively large sample size allowed us to observe that, among children with microcephaly, there is a spectrum of severity and different types of manifestations of the syndrome,” she added. “Now, we are better equipped to provide answers to the public health system.”
Demócrito Miranda, a professor at the University of Pernambuco (UPE), stresses that the main role of the study lies in consolidating knowledge that has been built up over the last ten years, since the beginning of the microcephaly epidemic, which was first identified in the Northeast.
Collapse
Maria Elizabeth pointed out that, in most cases, when a mother was infected during the fourth to the ninth month of pregnancy, the child’s brain would grow normally until it would suddenly experience cell destruction and collapse.
“It’s a different kind of microcephaly. It’s a different anatomy, so to speak. It’s very typical of Zika disease in pregnancy. In other cases of microcephaly, the brain is small. With Zika, it’s not. You can clearly see that something’s different. The brain collapses, and the bone structure collapses along with it,” she reports.
The researcher adds that this is associated with neurological, auditory, and visual disorders, in addition to “a lot of seizures that are difficult for these families to control, related to epilepsy caused by Zika.”
Main results
Cristina Hofer, a professor at the Federal University of Rio de Janeiro (UFRJ), says that the most frequent sequelae were structural abnormalities of the central nervous system, detected by neuroimaging, in addition to abnormalities in neurological and eye exams. Noteworthy findings include:
- microcephaly at birth, observed in 71.3 percent of cases, of which 63.9 percent were severe;
- postnatal microcephaly, recorded in 20.4 percent of children;
- prematurity, in 10 and 20 percent;
- low birth weight, with an average of 33.2 percent, ranging from 10 to 43.8 percent;
- and congenital malformations, among which the most frequent were epicanthus (40.1%), prominent occipital bone (39.2%), and excess skin on the neck (26.7%).
Among neurological alterations, the most frequent were social attention deficit in approximately 50 percent of children; epilepsy in 30 to 80 percent, with an average of 58.3 percent; and persistence of primitive reflexes in 63.1 percent.
With regard to sensory impairment, eyesight changes were observed in up to 67.1 percent of cases. Auditory changes were less frequent but present.
Neuroimaging tests also found cerebral calcifications in 81.7 percent, ventriculomegaly in 76.8 percent, and cortical atrophy in approximately 50 percent.
Maria Elizabeth pointed out that around 30 percent of the 853 children in the study have died. Those who remain alive are aged eight to ten years old and face difficulties in school inclusion in many cases. “Some cannot even attend school because they have severe cerebral palsy. Those who do attend have significant attention and learning deficits,” she remarked.
School life
After the study’s publication, researchers will continue to monitor children who had Zika, investigating the disease’s impact on school life.
“This is the greatest difficulty for children, especially those who do not have microcephaly, but whose mothers had Zika during pregnancy. When they are born, one group of these children has microcephaly, and the other does not. The group with microcephaly will develop a number of issues. But the other group needs to be monitored, because they may also have some developmental disorders,” the expert declared.
This monitoring is essential to ensure that early intervention can prevent more serious problems, she added. “Especially the generation born from 2015 to 2018 should have their neurodevelopment more carefully investigated by pediatrics in general,” she said.
