The virus selectively infects cells that form the brain’s cortex, or outer layer, making them more likely to die and less likely to divide normally and make new brain cells.
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“Our study shows once the virus gets to the brain it can reach these very important cells” , researcher Hengli Tang, the study’s lead author from Florida State University, said in an interview.
“This is a first step, and there’s a lot more that needs to be done”, Hongjun Song of the Johns Hopkins University School of Medicine said in a statement. The cases of babies born with birth defects have increased rapidly in Brazil, where the outbreak is largest. “Now you can be studying the virus in the right cell type, screening your drugs on the right cell type and studying the biology of the right cell type”. In as few as 3 days following exposure to the virus, 90% of the cortical neural progenitor cells in a lab dish had become infected. Cortical neural progenitor cells in turn give rise to immature neurons. It also appears the virus can harm fetuses in the third trimester, even if infection occurs earlier. Then the cells’ genetic expression – evidence of which genes were being used by the cells and which weren’t – were analyzed in Peng Jin’s laboratory at Emory University.
A recent study in Cell Press found that the Zika virus infects a type of neural stem cell that affects the brain’s cerebral cortex. Furthermore, the genes needed to fight viruses had still not been switched on, which is highly unusual, he adds.
The research, performed by a team of United States researchers, has highlighted exactly how the pathogen attacks fetal brain growth and triggers microcephaly. However, no abnormalities were found in the fetuses of women without Zika infections, the study noted.
The Zika virus was discovered in the 1940’s, and it usually results in flu like symptoms for adults.
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The virus is known to circulate in Africa, the Americas, Asia and the Pacific. Initially, transmission was thought to be exclusive to mosquito-borne vectors.
