Research using lab mice has shown for the first time that infection with the mosquito-borne Zika virus may damage adult brain cells, not just developing fetuses, said a study Thursday.
Adult cells involved in learning and memory can be destroyed by the viral infection, which is also blamed for a surge in the birth defect microcephaly, according to the findings in the journal Cell Stem Cell.
“Zika can clearly enter the brain of adults and can wreak havoc,” said co-author Sujan Shresta, a professor at the La Jolla Institute of Allergy and Immunology.
Researchers know that Zika can be “catastrophic for early brain development,” she added, but often adults who are infected show no symptoms.
Those who do feel sick may report rash, body pain, and red eyes.
“Its effect on the adult brain may be more subtle, and now we know what to look for,” said Shresta.
Researchers focused on neural progenitor cells, which are the early forms of brain cells that go on to become neurons.
Researchers describe them as the stem cells of the brain.
Zika can attack these neural progenitor cells in the developing fetuses, leading to microcephaly in babies, born with unusually small heads, brain damage and disabilities.
Adult brains retain some niches of these neural progenitor cells, which replenish neurons in parts of the brain linked to learning and memory.
Using fluorescent biomarkers in mice, the researchers saw that adult neural progenitor cells that were engineered to be vulnerable to Zika infection were killed off by the virus.
The study found that Zika infection was linked to a four- to 10-fold drop in the mice’s adult stem cell proliferation.
Two parts of the brain, including the hippocampus, which is associated with memory, saw evidence of cell death and reduced generation of new neurons, said the study.