WHO Director-General Dr Margaret Chan said the virus — which has been linked to birth defects and neurological problems — was becoming much more of a threat.

Brazil President Dilma Rousseff has called on the whole of Brazilian society to help combat the spread of the Zika virus, which has been linked to birth defects.

A final safeguard against the irresponsible development of gene drive technology is to ensure that early interventions are developed exclusively by governments and non-profit organisations.

The World Health Organization sets up a Zika "emergency team" after the "explosive" spread of the virus.

US scientists have urged the World Health Organisation to take urgent action over the Zika virus, which they say has "explosive pandemic potential".

The Rio de Janeiro authorities announce plans to prevent the spread of the Zika virus during the Olympic Games later this year.

Officials in four Latin American and Caribbean nations have warned women to avoid pregnancy amid concerns over an illness causing severe birth defects.