American specialists have urged the World Health Organization (WHO) to take urgent action over the Zika virus, which they say has “explosive pandemic potential”.

Writing in the Journal of the American Medical Association, the scientists called on the WHO to heed lessons from the Ebola outbreak and convene an emergency committee of disease experts.

They said a vaccine might be ready for testing in two years but it could be a decade before it is publicly available.

Zika, linked to birth defects as microcephaly, has caused panic in Brazil.

Thousands of people have been infected there and it has spread to some 20 countries.

Brazilian President Dilma Roussef has urged Latin America to unite in combating the virus.

Dilma Rousseff told a summit in Ecuador that sharing knowledge about the disease was the only way that it would be beaten. A meeting of regional health ministers has been called for next week.

In the JAMA article, Daniel R. Lucey and Lawrence O. Gostin say the WHO’s failure to act early in the recent Ebola crisis probably cost thousands of lives.

They warn that a similar catastrophe could unfold if swift action is not taken over the Zika virus.

“An Emergency Committee should be convened urgently to advise the Director-General about the conditions necessary to declare a Public Health Emergency of International Concern,” Daniel R. Lucey and Lawrence O. Gostin wrote.

They added: “The very process of convening the committee would catalyze international attention, funding, and research.”

White House spokesman Josh Earnest said on January 27 the US government intended to make a more concerted effort to communicate with Americans about the risks associated with the virus.

There is no cure for the Zika virus and the hunt is on for a vaccine, led by scientists at the University of Texas Medical Branch.

The researchers have visited Brazil to carry out research and collect samples and are now analyzing them in a suite of high-security laboratories in Galveston, Texas.