Brazil urged its neighbours to unite in fighting the Zika virus, blamed for a surge in brain-damaged babies, as airlines offered refunds to pregnant mothers afraid to travel to the region.
As alarm rose over the latest world health scare, US President Barack Obama called for faster research on the quick-moving virus, which has infected travellers from the United States and Europe.
Brazil has been the country hardest hit by the outbreak of the mosquito-borne virus, which is blamed for a sharp rise in infants born with microcephaly, or abnormally small heads.
The outbreak is particularly concerning officials as the country prepares to host the Olympics, which will bring hundreds of thousands of travellers from around the world to Rio de Janeiro in August.
Zika has spread to some 20 countries in Latin America and the World Health Organisation (WHO) expects it to spread to every country in the Americas except Canada and Chile.
Denmark and Switzerland joined a growing number of European countries to report Zika infections among travellers returning from Latin America.
There is currently no specific treatment for Zika and no way to prevent it other than avoiding mosquito bites.
Brazilian President Dilma Rousseff said yesterday she had asked a summit of the 33-member Community of Latin American and Caribbean States (CELAC) to launch "cooperative action in the fight against the Zika virus."
An American Airlines spokesman said the company was offering refunds to pregnant women with flights booked to Brazil and 10 other countries and territories affected by the virus.
Another US airline, Delta, said some its passengers may also qualify for a refund or a change to their tickets.
Zika originated in Africa and also exists in Asia and the Pacific, but has not been associated with microcephaly there. It first came to prominence in Brazil in October.
Microcephaly can cause brain damage or death in babies.
In Brazil, cases of microcephaly have surged from 163 a year on average to more than 3,718 suspected cases since the outbreak, according to the health ministry.
Sixty-eight of the babies have died.
Colombia, Ecuador, El Salvador and Jamaica have warned women to avoid getting pregnant for the time being.
Costa Rica said yesterday it was introducing health questionnaires for travellers entering the country to detect possible carriers of the virus.
