The Zika virus is transmitted from a mother to her fetus by infected cells that will later develop into the brain's first and primary form of defense against germs, scientists at the UC San Diego School of Medicine reported Friday.
The discovery could open a pathway for a potential treatment for infected patients.
Awareness of the virus dramatically increased last year when a cluster of women in Brazil gave birth to babies with microcephaly, a condition in which their heads are smaller than normal, leading to developmental difficulties.
Formost non-pregnant woman, the virus only resulted in mild symptoms, health officials said. Zika is spread from mosquitoes to humans in tropical regions, but the method of transmission from a pregnant mother to her unborn child wasn't aswell understood.
The new findings from UC San Diego scientists and colleagues in Brazil, were published in the online edition of Human Molecular Genetics.
“It's a Trojan Horse strategy,'” said Alysson Muotri, a professor in the UC San Diego departments of pediatrics, and cellular and molecular medicine.
She said that during the early stages of prenatal development, cells called microglia form in the yolk sac and then disperse throughout the central nervous system of the developing child. In the brain, the microglia clear away plaques, damaged cells and infectious agents, she said.
“Our findings show that the Zika virus can infect these early microglia, sneaking into the brain where they transmit the virus to other braincells, resulting in the devastating neurological damage we see in somenewborns,'' Muotri said.
The scientists also found that a drug called Sofosbuvir, marketed as Sovaldi and used to treat hepatitis C, limited the impact of the virus on the eveloping brain.
Muotri said the finding was encouraging. But she cautioned that since it was only based on laboratory testing, more investigation is needed.
Researchers at the University of Sao Paolo in Brazil participated in the study, which was funded by the California Institute for Regenerative Medicine, the National Institutes of Health, Zika Network FAPESP of Sao Paolo, UCSD Tooth Fairy Project and the A.P. Giannini Foundation of San Francisco.