Zika infects brain cells, evades immune system detection

Washington: The mosquito-borne Zika virus,linked to serious birth defects, avoids immune system detection and directly infects the brain cells destined to
become neurons, a new study has found.

Researchers used a strain of Zika currently impacting the Americas, and found that the virus infects about 20 per cent of cells on average, evades immune system detection, and continues to replicate for weeks. "The cellular system we studied mirrors what pathologists are finding in the brain tissue of affected infants and will be valuable for further understanding of how Zika causes severe brain-related problems," said John Schoggins, assistant professor at University of Texas Southwestern Medical Centre(UT Southwestern) in the US.

"The system may also serve as a platform for testing new therapies targeting the virus," said Schoggins. Zika can be spread by infected mosquitoes or through
sexual intercourse. In adults, the symptoms are generally mild and include fever, rash, joint pain and red eyes. However, Zika virus can cause a serious birth defect called microcephaly, and other severe neurological effects such as eye problems, hearing loss, and impaired growth in infants born to women who contracted the virus when pregnant, researchers said.

"There was a suggestion that the detrimental effects of the virus might be linked to its ability to infect brain cells, specifically the progenitor cells that give rise to
neurons," said Schoggins. "We showed that neural progenitors can be infected by a strain of Zika virus that is currently infecting people in the Americas," Schoggins said. "We found that the virus kills some neural progenitor cells, but not all. Other cells survive the infection, and surprisingly, continue to replicate the virus for many weeks," he said.

"In addition, it appears that Zika virus does not stimulate much of an immune response," he added. The study was published in the journal Cell Reports.