The Atlanta-based agency is warning pregnant women to avoid more than 30 areas where the Zika virus is actively spreading.
Advertisement
The Zika virus is capable of quickly infecting and harming developing fetal brain cells, scientists said on Friday in a study that provides insight into how the virus might cause the birth defect microcephaly in fetuses exposed in the womb.
In the first study, researchers followed 88 pregnant women who sought care for a rashlike illness at the Oswaldo Cruz clinic in Rio between September 2015 and January 2016. Two babies were stillborn, at 36 and 38 weeks.
Dr Guo-li Ming, a professor of neurology, neuroscience, psychiatry and behavioral science at Johns Hopkins University in Baltimore, said: “Studies of foetuses and babies with the telltale small brains and heads of microcephaly in Zika-affected areas have found abnormalities in the cortex, and Zika has been found in the foetal tissue”.
Those travelling to areas where the virus has been recorded are advised to wear long-sleeves and long clothes to prevent mosquito bites, use topical mosquito repellents, and stay in cool, air-conditioned areas indoors.
The new results mark the first from a prospective study, which involves tracking the health of women who are infected with Zika and comparing them to very similar people who are not infected. Two of the infants had lesions in their eyes, which could indicate blindness. Another was delivered by emergency cesarean section due to no amniotic fluid.
The study from Brazil, reported Friday in the New England Journal of Medicine, took a closer look during pregnancy. No fetal abnormalities were detected in any of the 16 women who tested negative for Zika.
Concern about a possible link sparked a rush of studies to test the possibility, as well as explore whether the virus is causing other problems.
“We know when the infection is taking place”, she said.
Laboratory tests found that the virus targeted key cells involved in brain development and then destroyed or disabled them, they said. They compared the virus’s effect on cortical neural progenitor cells with its effect on two other cell types: induced pluripotent stem cells and immature neurons.
“Although our study hasn’t provided a direct link between Zika virus and microcephaly, we identify the direct cell targets of the virus and we show the virus can affect cell growth”, said study co-author Zhexing Wen, a postdoctoral fellow at the Johns Hopkins University School of Medicine in Baltimore.
A team of U.S. researchers has discovered what they believe could be the mechanism by which the mosquito-borne virus hinders brain development in unborn children.
Advertisement
“I think the study is going to be incredibly important to the understanding of how microcephaly develops”, said Jeanne Sheffield, a maternal health expert at Johns Hopkins University who did not participate in the study, in a university announcement. Its attack made those cells more likely to die and less likely to divide normally and make new brain cells, the Washington Post reported.
