A new study by scientists at the Oswaldo Cruz Institute has detected the Zika virus in the amniotic fluid of two pregnant women whose fetuses were diagnosed with microcephaly, suggesting that the virus can cross the placental barrier. However, further research will need to be conducted in order to prove a causal link between the virus and microcephaly.
The study also examined the entire genome of the virus discovered in the two women in the study and found that the virus is genetically related to the strain responsible for the outbreak in French Polynesia in 2013.
"Previous studies have identified Zika virus in the saliva, breast milk and urine of mothers and their newborn babies, after having given birth. This study reports details of the Zika virus being identified directly in the amniotic fluid of a woman during her pregnancy, suggesting that the virus could cross the placental barrier and potentially infect the fetus,"
, lead author of the study, said in a press release.
During the study, the team examined two women, ages 27 and 35, from Paraiba, a state located in northeast Brazil. Each patient showed symptoms of Zika including rash, fever and muscle pain, and ultrasounds conducted at 22 weeks of pregnancy confirmed the presence of microcephaly in the fetuses.
The team took amniotic fluid samples at 28 weeks of pregnancy and analyzed them using metagenomic analysis - the results showed the presence of the Zika virus genome, despite their blood and urine samples testing negative for the virus.
"Even if all these data strongly suggest that Zika virus can cause microcephaly, the number of microcephaly cases related to Zika virus is still unknown," said Didier Musso, a professor who did not participate in the research. "The next step will be to do case-control studies to estimate the potential risk of microcephaly after Zika virus infection during pregnancy, other fetal or neonatal complications, and long-term outcomes for infected symptomatic and asymptomatic neonates."
The findings were published in the Feb. 17 issue of The Lancet Infectious Diseases.
