New York, Jan 20 : Zika virus disrupts oxygen supply to a pregnant woman's placenta, leading to impairment in foetal development and also increases the newborns' susceptibility to additional infections, scientists have found.
The findings showed that Zika virus induces high levels of inflammation in the blood vessels of the uterus and damages placental villi, the branch-like growths that help transfer oxygen and nutrients from maternal blood to the fetus.
This damage may disrupt oxygen transport to the foetus, which can restrict its growth and lead to stillbirth, among other conditions.
"The role of a placenta is to protect and provide nutrition to a growing baby for optimum health," said Antonio Frias, an obstetrician and gynecologist at Oregon Health and Science University.
"It's concerning how much damage the Zika virus can do to a placenta," Frias added.
In a study, published in the journal Nature Communications, the team described how Zika virus infection in five pregnant rhesus monkeys caused placental tissues to become thickened and inflamed.
As a result, the researchers saw less oxygen being transported across the placenta and to the baby.
Decreased oxygen levels in a placenta can impair foetal development and ultimately the health of a baby after it is born.
The researchers used a non-invasive, in vivo MRI technique to evaluate oxygen levels inside the placenta and oxygen flow between mother and baby.
They found that, in monkeys that were infected with Zika early in their pregnancies, the rate of oxygen transport through the placenta decreased about 10-fold.
The researchers also determined that the Zika virus can readily pass from mother to baby and remain in the baby long-term, leading to a chronic infection in utero.
By better understanding how both mother and child become infected with and affected by the Zika virus, researchers can determine how to prevent its infection and disease.