In a new paper in the New England Journal of Medicine, Mlakar and colleagues present some compelling evidence for the presence of Zika virus (ZIKV) in brain tissue of a foetus, probably infected by the mother (vertical transmission), that was medically terminated because of severe brain disease, microcephaly and a poor prognosis.
This study has a very strong title: Zika Virus Associated with Microcephaly
…and it can make that claim because of several robust findings.
- Presence of flavivirus-like particles in foetal brain as imaged using electron microscopy, which the authors suggest may reflect persistence in an immune-privileged site. They don’t have data to support that though but presumably infection would need to persist for long enough to cause the structural damage seen in these diagnoses – whether that must begin within the first trimester has not been shown, just hypothesized. We do know that virus in the blood usually clears in a week, with virus detectable in the urine for a little longer
- Detection of viral RNA in the brain tissue at levels, or ‘viral load’, higher than usually reported in adult ZIKV patients
- Detection of antibodies in the mother’s serum indicating past ZIKV, and also Dengue virus, infections
- Determination of a complete, full-length genome of the Asian clade of ZIKV, from the foetal brain tissue (KU527068) using an Ion Torrent deep sequencing approach
- Absence of ZIKV RNA in many other tissues
- Absence of finding other viral genetic material which were sought and included dengue viruses, chikungunya virus, cytomegalovirus, herpesviruses, enteroviruses, rubella virus and others
This content was originally published at http://bitly.com/1Kas2vY