The Zika virus has sparked global alarm largely because of fears that the pathogen is causing microcephaly, a condition in which babies are born with unusually small heads and damaged brains.
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One concerning discovery was that the cells that Zika infected became factories for viral replication.
The scientists took lab-grown neural stem cells and neural progenitor cells – the building blocks of the brain – and infected them with the Zika virus in culture dishes.
Song’s team also reported that the infected cells grew more slowly than healthy cells, and their division cycles were interrupted – factors that could also contribute to microcephaly.
A small study published on Friday in the New England Journal of Medicine found evidence of a range of severe fetal abnormalities apparently linked to Zika virus in pregnant women in Rio de Janeiro. Researchers say the Zika virus may be linked to a wider variety of ¿grave outcomes¿ for developing babies than previously reported and that threats can come at any stage of pregnancy.
In contrast, the two other human cell types tested in this laboratory experiment (stem cells and neurons) were largely spared Zika.
The new study does not answer an important question: whether Zika infections so mild that they produce no symptoms in the mother can damage a fetus.
While bolstering the connection between Zika virus and brain defects in babies, one of the researchers cautioned that it doesn’t establish a conclusive link.
There’s no evidence that the cells are employing antiviral responses, which means we don’t know whether or how the virus is being cleared from the precursor cells, said Ming, a neuroscientist interested in brain disorders like microcephaly.
“And that’s the reason we’ve asked the Emergency Committee again next week to convene and look at these data”, the WHO’s Aylward said, referring to a group of independent experts chaired by David Heymann.
Ms Garin said it was only the second Zika case to be reported in the Philippines and stressed that there has been no report of an outbreak.
The hNPCs are crucial for the development of the cortex – or outer layer – of fetal brains, and the findings would be consistent with the theory that Zika can cause microcephaly. But the missing relationship is how the infection can depress or stagnate brain development in utero.
When scientists in Brazil suspected a link between a troubling upswing in a birth defect called microcephaly and the mosquito-borne Zika virus last fall, the hunt began for proof.
The preliminary results are based off of the first 42 Zika infected women who agreed to ultrasounds.
The Zika virus has reached epidemic proportions in many parts of South America, prompting U.S. officials to issue travel advisories.
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No cases have been reported of Zika infections acquired from mosquitoes within the United States.
