Zika virus has been detected in the brain of an aborted microcephalic fetus. The autopsy revealed structural brain abnormalities and high levels of the virus.
The noose is tightening around the Zika virus. The discovery of the link between infection in pregnant women and the occurrence of microcephaly in the fetus has just come a long way. The autopsy of an aborted microcephalic fetus reveals the presence of the virus in its brain. This is the revelation of a case study published in the New England Journal of Medicine.
The young mother behind this publication is a 25-year-old European who volunteered for two years in Natal, Brazil. It was during his 13e week of gestation that she contracted the Zika virus. Back in Slovenia, ultrasounds performed between 14 and 20 weeks did not indicate any anomaly.
Calcifications in the brain
But the young woman notices less mobility of the fetus and goes to the perinatology department of the university hospital in Ljubljana. The ultrasound confirms, at the 29e week of amenorrhea, growth retardation and microcephaly, a birth defect characterized by underdevelopment of the skull. The prognosis is bad. The mother decides on a medical termination of pregnancy, approved by the State and carried out at 32 weeks gestation.
The autopsy of the fetus is then performed routinely. But this has boosted knowledge about the Zika virus by leaps and bounds. Doctors confirm that the child has microcephaly and severe brain damage. Instead of presenting the usual grooves, the organ is smooth on the surface and calcified in places in the cerebral cortex. This suggests the presence of inflammation during fetal development. Some areas are completely absent, and the brainstem and spinal cord suffer from hypoplasia.
Very high rates
In particular, forensic scientists were able to observe high levels of Zika virus in brain tissue, much higher than those usually detected in blood samples. Its genome belongs to the strain present in French Polynesia since 2013 and sequenced in Brazil since 2015.
The autopsy also shows a specific action of the virus: it acts only on the brain. No other organ of the fetus shows any trace of it and no other malformations were observed.
This set of signs “reinforces the biological association” between Zika virus infection and microcephaly, in the eyes of Dr Eric Rubin, Michael Green and Lindsey Baden who comment on this case study in an editorial. However, it is becoming urgent to confirm it: in Brazil alone, 4,000 suspected cases have been reported to the authorities, 400 confirmed cases. The virus has been spotted in 17 babies.
The virus identified by the American authorities
The timing is perfect for the US authorities. The Centers for Disease Control and Prevention (CDC) have announced that they have identified the Zika virus in the tissues of two babies who died of microcephaly in Brazil. “This is the strongest evidence to date that Zika is the cause of microcephaly,” said their director Tom Frieden. He added, however, that the virus does not cause this birth defect and that more testing is needed to show a link.
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