The Zika Virus riddle has finally been unravelled. US officials have confirmed that Zika virus is indeed linked to brain defects in infants born to women who are infected with the virus.

The revelation on Monday was unfolded in a review by the Centres for Disease Control(CDC), which featured the study online in the New England Journal of Medicine.

“There’s still a lot that we don’t know. But there is no longer any doubt that Zika causes microcephaly,” said Dr. Tom Frieden, chief of the CDC in a report by NPR.

“And it is because this was so unprecedented that we have until now awaited to say that we have concluded that there is a causal link,” he added.

Zika virus was first identified in Brazil in 2015 and has now encapsulated the South Americas and the Caribbean. It was initially not a serious issue, but as it expanded and caused birth anomalies among newborns, authorities rang the alarming bells and people were advised to stay away from the mosquito bite. Now, United States is among the ones at risk.

Meanwhile, Zika was also linked to Guillain-Barré syndrome, which affects the nervous system and attacks immune system causing weakness.

The team of researchers used two procedures to untangle the truth.

The first procedure digs down the correlation between “a rare exposure and a rare defect”. This method was once used to confirm rubella on pregnancy, which causes brain damage and hearing loss.

The second approach analysed the Zika outbreak-trend in Brazil and French Polynesia which successively increased birth defect cases. Moreover, researchers analysed the cases of pregnant women who visited Zika-affected regions and gave birth to babies having microcephaly.

According to NBC News, the study revealed that Zika attacks foetus’s brain and kill the cells and prevent it from growing. And it affects in all the stages of pregnancy.

However, experts are still on doubt how gravely the virus will damage the brain of a baby when women are pregnant in contrast with the ones who are infected and don’t suffer from symptoms.