Their findings are published in the 10 February issue of New England Journal of Medicine and are considered exceptionally important as the link between Zika and microcephaly had heretofore been suspected but not confirmed.

The team, from the University of Ljubljana's Medical Faculty and two departments of UKC Ljubljana, thus confirmed that Zika can pass from an infected mother to the brains of the foetus, causing permanent damage.

The researchers performed autopsy on a foetus aborted in week 29 after a sonogram showed brain anomaly. The mother, a Slovenian woman who did volunteer work in Brazil, was infected with Zika at week 13.

The autopsy showed the presence of Zika in brain tissue but no traces of 13 other viruses that could potentially cause microcephaly.

The team will present the findings at a press conference at UKC Ljubljana at noon today.