As scientists delve deeper and deeper into Zika, it seems like they’re finding hidden effects and perils almost each time. We previously reported, for instance, that the virus affects both the fetal and adult brain, possibly causing memory loss and cognitive diseases in the latter. Now, a new paper published in Radiology suggests the virus can inflict damages to many parts of the brain, previously thought to be unlinked with microcephaly.
The findings were made by a group of international researchers who used brain scans and ultrasound imaging on 45 Brazilian babies whose mothers were infected with Zika during pregnancy. All but three babies were born with microcephaly — a dreaded condition which causes babies to develop abnormal heads. This abnormality is due to a poorly developed brain during pregnancy. As reported earlier, the abnormally small brains are likely due to the fact that Zika kills a lot of neural progenitor cells in the fetus’ brain.
These latest images, however, suggest the impact Zika has on the brain is significantly more profound. The new analysis proves that Zika targets the corpus callosum, a wide, flat bundle of neural fibers that sits right between the two brain hemispheres and facilitates communications between them; the cerebellum, which is vital for coordinating movement, balance, and speech; and also the basal ganglia, which is involved in thinking and emotions.
Perhaps the most interesting finding was the calcification of the cortex. This is an unusual place for bundles of calcium to form, a common symptom for infections that attack the brain, and this knowledge could serve to identify or rule out Zika infections a lot earlier, maybe from the second trimester.
“The brain that should be there is not there,” said Dr. Deborah Levine, an author of the study and a professor of radiology at Harvard Medical School. “The abnormalities that we see in the brain suggest a very early disruption of the brain development process.”
“I think we were all aware that Zika causes brain abnormalities, but it’s been more generic,” said Dr. Rita Driggers, an associate professor of gynecology and obstetrics at Johns Hopkins University School of Medicine, who was not involved in the study, told the NY Times. “Now we know more specifically what we’re looking for in terms of brain abnormalities before the microcephaly occurs.”
The fact that Zika also damages the cortex is perhaps most worrisome. Researchers say this is a critical area for brain development since it is here that certain chemicals become released that signal where new neurons should grow, find their place and start making connections. It’s likely that Zika scrambles this process causing severe neural messaging and connectivity problems in the brain. Sadly, the full extent Zika will have on the lives of these babies will be uncovered only much later once they grow up — and it won’t be pleasant for anyone.