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 The findings, published on Wednesday in a letter to the New England
Journal of Medicine, are based on a large trove of computed
tomography, or CT images, done in infants whose mothers are believed
to have had Zika infections during pregnancy.
The study included researchers from Brazil's Northeastern state of
Pernambuco, such as Dr. Ana van der Linden of the Instituto de
Medicina Integral, who were among the first to sound the alarm about
increasing cases of microcephaly in Brazil thought to be linked with
Zika infections.
Microcephaly is a typically rare birth defect marked by unusually
small head size, signaling a problem with brain development. Brazil
is investigating thousands of cases of microcephaly and has
confirmed more than 940 cases to be related to Zika infections in
the mothers.
Scientists in the study ran several tests on the mothers to try to
rule out other possible causes of microcephaly, including
toxoplasmosis, cytomegalovirus, parovirus, HIV and rubella. All were
all negative. All of the mothers had symptoms during their
pregnancies - such as fever and rash - that were consistent with
Zika infections. Testing on spinal fluid from seven of the infants
was positive for Zika antibodies.
The researchers did CT scans when the babies were between three days
and five months old. All showed signs of brain calcification, which
is suggestive of brain inflammation. Many of the babies had other
abnormalities, including brain swelling, disruptions in brain folds,
underdeveloped brain structures and abnormalities in myelin, which
forms protective sheaths on nerve fibers.
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Researchers said the findings were consistent with a study published
last month testing lab dishes full of nerve stem cells similar to
those in the brains of human fetuses. They showed that the Zika
virus was able to easily infect these cells, stunting their growth.
Researchers said evidence from the brain scans suggests the
abnormalities occurred from a disruption of brain development,
rather than a destruction of brain cells.
According to the World Health Organization, there is a strong
scientific consensus that Zika can cause microcephaly, although
conclusive proof may take months or years.
(Reporting by Julie Steenhuysen; Editing by Leslie Adler)
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