New York: Zika virus is capable of replicating and spreading infectious particles within the outermost cells lining the vaginal tract, say researchers. The findings provide molecular-level insights into how the virus can move from person to person through sexual contact.
While Zika is primarily spread by mosquitoes, researchers have been aware of its potential for sexual transmission based on cases in which people became infected after having sex with a partner who had visited a Zika-affected area. Previous studies have also found Zika particles present in semen and vaginal fluid from infected individuals.
"The outcome of this research highlights how local replication of Zika in the vaginal epithelium plays an important role in mediating sexual transmission and subsequent systemic infection in the human host," said lead study author James Mungin Jr from Meharry Medical College in the US.
For the current study, published in the journal FASEB Journal, Athe research examined how Zika particles behaved in cultures of human vaginal epithelial cells and identified the virus's likely entry point as a protein on the surface of the cells called tyrosine-protein kinase receptor UFO, which is encoded by the AXL gene.
"Our research findings confirming that the receptor UFO (AXL) promotes viral entry can be very instrumental in developing drugs and antibody-based therapies that target and block this receptor, therefore eliminating the pathology caused by this virus," Mungin Jr added.
According to the researcher, while the number of cases has since dropped precipitously, the virus is still considered a health threat in many places around the world. Babies born to mothers infected with Zika have a high risk of birth defects.The findings showed that Zika virus particles were able to successfully enter vaginal epithelial cells through the UFO receptor, replicate their RNA genome and steadily release infectious viral particles inside the cells.
The research team plans to further study the factors that contribute to Zika replication for insights on how those factors might be interrupted.Like Zika, many other viruses in the flavivirus family are spread by insects. However, research on those other viruses, such as dengue and yellow fever, does not always translate well to Zika because they are not sexually transmitted, the authors wrote.
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