Daffodil International University
Faculties and Departments => Faculty Sections => Topic started by: ABM Nazmul Islam on March 09, 2016, 11:55:13 AM
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The prime suspect in Brazil’s recent surge in birth defects may be convicted this summer, in the sweltering cities of Colombia.
That’s when the first big wave of pregnant women infected with Zika virus last fall will begin to give birth. Whether or not these babies are born with stunted brains, a condition known as microcephaly, may offer the best evidence yet that Zika is the culprit — or not.
While the world waits, molecular evidence is starting to come in. Zika virus readily infects (and kills) one kind of brain cell in developing embryos, researchers report online March 4 in Cell Stem Cell. “It’s the first step to show that Zika is actually doing something in the brain,” says study coauthor Guo-Li Ming, a neuroscientist from Johns Hopkins School of Medicine. Previous studies have found traces of Zika in damaged fetal brains — but that’s just a correlation.
ABNORMALLY SMALL Babies with microcephaly have head circumferences that are two standard deviations below average (middle). Three standard deviations below average is considered severe microcephaly (bottom).
CDC
Still, correlations like these may be why the mosquito-borne virus has sparked so much panic. In the last year, Zika has torn through Brazil and invaded 40 other countries and territories. Now, Zika infection during pregnancy is the leading theory for why so many babies have been born with microcephaly in Brazil. Suspected cases of the rare birth defect are showing up at more than 30 times the rate of previous years.
Seeing microcephaly numbers skyrocket in other countries could make or break the case. So far, only Brazil has reported an uptick in microcephaly (though French Polynesia did in an earlier outbreak). Still, evidence that Zika is to blame remains circumstantial.
“We don’t have absolute proof,” says Christopher Dye, a strategy director of the World Health Organization. But scientists do have enough evidence to consider the virus “guilty until proven innocent,” he says.
University of Pittsburgh public health researcher Ernesto Marques agrees. “We have a victim, and we have a suspected criminal with a gun.” Now, he says, “we have to prove who pulled the trigger.”