The Zika virus might not only affect the fetuses of pregnant women but also the brains of adults, according to new research in mice.

While there have been many studies looking at the virus’s effect on the developing brain, this study is the first to look at the effect of Zika infection in adult brain cells.

Joseph Gleeson, the study’s lead author and professor at Rockefeller University, and his colleagues used engineered mouse models to mimic the Zika infection in humans. Using fluorescent biomarkers they were able to light up the parts of the brain that were damaged by the virus.

Results showed that adult brain cells, particularly ones that are thought to be crucial in learning and memory, may be vulnerable to infection.

“We don’t want this to produce panic or fear,” Gleeson, whose study was published Thursday in the journal Cell Stem Cell, told in a phone interview from New York, adding: “but Zika may not be as innocuous as people think.”

The Zika virus, which has rapidly spread in Central and South America in the last 8 months, is known to have damaging effects on developing fetuses including smaller-than-normal heads and a number of developmental disabilities.

While it may cause irreparable damage for early brain development, most adults who are infected with Zika show only mild symptoms, if any at all.

Based on the study’s findings it’s the same mechanisms that damage fetuses that also wreak havoc in the adult mouse brain.

"Our results are pretty dramatic -- in the parts of the brain that lit up, it was like a Christmas tree," he said.

Gleeson explains that Zika attacks a group of brain stem cells, known as neural progenitor cells.

“It had two major effects,” he said, “it stopped cells dividing and it had a huge effect on cell death.”

While they don’t know for certain the long-term impact of the virus, Gleeson theorizes that it could affect long-term memory.

More research will be needed to see if what Gleeson and his colleagues observed in mice also happen in humans, and more immediately, Gleeson is keen to see if the stem cells can bounce back.