Countries including South Africa and Trinidad and Tobago have confirmed their first cases of Zika virus.
More than 5,000 pregnant women in Colombia have contracted the virus, its government has said.
More than 200,000 Brazilian soldiers have been out on the streets today as part of an education drive to combat the spread of the Zika virus.
The troops are handing out leaflets and aim to reach three million homes in 350 cities.
Video report by ITV News' reporter Helen Callaghan
Britain's camp for the Rio Olympics should be moved to a Zika-free location outside Brazil, Jessica Ennis-Hill's coach has said.
The mother of Zika "bucket baby" Jose Ferreira is holding out hope despite doctors' fears over his future.
The government has told airlines to take the measure on all flights travelling to the UK from countries with confirmed transmission of Zika.