The current Ebola virus outbreak in West Africa is the largest the world has ever seen, U.N. Secretary-General Ban Ki-moon told the Security Council Thursday.

“The number of cases is doubling every three weeks. There will soon be more cases in Liberia alone than in the four-decade history of the disease”, Ban told delegates.

The outbreak of the deadly disease is unprecedented in scale and threatens to undermine peace and security in Africa, according to the United Nations.

The spreading crisis also prompted a meeting of the Security Council, the most powerful body at the United Nations.

The Geneva-based World Health Organisation (WHO) has said more than 5,500 people have been infected and well over 2,500 have died.

The United Nations says at least one billion dollars will be needed over the next six months to halt the spread of the disease.

“The gravity and scale of the situation now require a level of international action unprecedented for a health emergency”, said Ban, who announced the establishment of an U.N. emergency health mission with a strong WHO component.

“This international mission, to be known as the United Nations Mission for Ebola Emergency Response, or UNMEER, will have five priorities: stopping the outbreak, treating the infected, ensuring essential services, preserving stability and preventing further outbreaks.”

Margaret Chan, Director General of WHO, briefed the Security Council Thursday describing the spreading virus as the greatest peacetime challenge the U.N. has ever faced.

“This is not just a public health crisis. This is a social crisis, a humanitarian crisis, an economic crisis, and a threat to national security well beyond the outbreak zones.”

Briefing the Security Council, David Nabarro, Senior U.N. System Coordinator for Ebola, said the outbreak of the disease has advanced in an exponential fashion, while the response was increasingly on a linear graph.

“I estimate, that to get ahead of the outbreak, the level of response has to be 20 times greater than it is at the moment”, Nabarro added.

The outbreak had a strong impact on the health systems of the three most affected countries — Liberia, Guinea and Sierra Leone– and currently more people are dying for untreated common medical conditions than for Ebola, Ban said.

Women are mostly been affected since they constitute the bulk of health and care workers and get infected more.

The economic and productive system is also at risk, fields are not being farmed, and a food crisis is posing serious worries.

There has been a widespread appeal to major airlines, shipping companies and governments to resume services to the affected countries.

“Isolation only hampers international efforts to reach people in need”, said Ban.

Many member states and organisations have pledged consistent donations in cash, medical staff, infrastructures, laboratories, training, prevention kits and much more.

A Security Council resolution, initiated by the United States and aimed at battling the disease, was co-sponsored by more than 134 states.

“But if today’s resolution is not followed by action on a scale and scope commensurate to the virus, this resolution will be cited years from now as evidence that we raised hopes that we didn’t deliver on”, remarked U.S. Ambassador Samantha Power.

Chan said she will ensure actions will follow commitments.