As you are probably aware, the Zika virus has been steadily establishing itself in South America, Central America, the Caribbean, and now, in parts of the U.S. Until now, most researchers have believed that Zika virus is relatively weak and even harmless in the majority of adults, and that the only significant risk is to pregnant women and the babies they carry. Pregnant women infected with Zika may pass the virus to their fetus, which can cause birth defects like microcephaly, hearing loss, impaired growth, or fetal demise (stillbirth.)
However, recent research from The Rockefeller University has found that Zika can also have long-lasting deleterious consequences for adult brain cells. This new study, the first that looks at the effects of Zika in adult brain cells, was just published in Cell Stem Cell. The investigators looked at the brains of adult mice and found that the effects of Zika on the adult brain may not be as obvious as those seen in fetuses, but may still be quite harmful.
In both adults and fetuses, the Zika virus attacks a type of brain cell called “neural progenitor” cells. In the fetal brain, prior to brain cell specialization, the entire brain consists of neural progenitor cells, which is why the Zika virus is so incredibly harmful to developing brains. But adults still maintain a reserve of neural progenitor cells in the brain—most notably, in two brain areas that are related to learning and memory. The Rockefeller study used fluorescent biomarkers and found that in the adult mouse brains, the Zika virus was targeting these neural progenitor cells and hitting them hard.
Of course, since this is a mouse study and the first of its kind, much more research is needed to discover the full effects of Zika on the adult brain. But it is a good reminder that there is still a great deal we need to learn about the Zika virus in order to understand it fully.
- Li, H, Saucedo-Cuevas, L, Regla-Nava, JA, Chai, G, Sheets, N, Tang, W, Terskikh, AV, Shresta, S, and Gleeson, JG. (2016.) Zika virus infects neural progenitors in the adult mouse brain and alters proliferation. Cell Stem Cell, August 18, 2016 (online.)