Although most risk associated with Zika so far has focused on infants, it turns out that adults might not be in the clear.
Researchers from Rockefeller University and the La Jolla Institute for Allergy and Immunology say there’s evidence that Zika could inflict our brain’s stem cells, even as adults. The team reported their findings in a study published in the journal Cell Stem Cell.
The scientists exposed adult mice to Zika and found that brain areas containing a specific type of neural cell—once thought to be resistant to the Zika virus—had become severely infected. Whereas fetal infection with Zika spreads evenly throughout the brain, the team found that adult infections are limited to areas hosting these neural stem cells.
Here’s Amrith Ramkumar, writing for Bloomberg News:
The stem cells, known as neural progenitor cells, help replace damaged neurons—the main components of our brain and spinal cord—and assist with learning and memory. Using a mouse model, the researchers found that Zika can target those cells, which can lead to reduced brain volume and complications in brain functioning—similar to the long-term effects of microcephaly.
“Getting infected with Zika as an adult may not be as innocuous as people think,” Joseph Gleeson, the study’s lead author and head of Rockefeller’s pediatric brain disease laboratory, said in a release.
Rates of brain damage among babies infected with Zika are uncertain, but this new study indicates that more people could be adversely affected by it than originally thought. In addition, the study may shed light on why Zika has been linked to Guillain-Barré syndrome, a disorder in which the body’s immune system attacks its nervous system. Until the study is replicated in humans, though, these results can’t hold up as solid evidence that Zika has the potential to harm adult brains to the same extent as fetal brains.