WATCH: What we know about the Zika virus, so far

It is one of the biggest public health emergencies in the world.

Millions are on the move, and the number of people in need of urgent assistance is growing.

But for now, it remains a mystery as to whether Zika is spreading anywhere else in the Americas.

The first symptoms of the virus were first reported in Brazil last year, and experts are unsure if they are linked to travel or other factors.

A WHO spokesman told Reuters on Tuesday that there is “no conclusive evidence” that the virus is spreading further.

The WHO, the U.N. and the World Health Organization have all been warning that Zika poses a threat to the health of people living in the affected regions.

The World Health Assembly, the United Nations health body, on Tuesday adopted a statement calling on countries to stop the spread of Zika, which was adopted after an emergency meeting of the body’s emergency committee in Geneva.

The committee, which includes representatives of the countries most affected, will meet again on Wednesday to discuss the latest recommendations for a global response to the virus.