The Ebola death toll plaguing three nations in West Africa has reached 2,461, the World Health Organisation said on Wednesday. The United Nations said over U.S.$1 billion is needed to eradicate and control the rampaging outbreak.

Nearly half of the cases, according to the WHO, were recorded in just the past three weeks alone. This is an indicator that efforts to stop the disease from spreading are going haywire.

As of Sept. 13, Ebola had killed 595 people in Guinea, where the outbreak began at the start of the year. There were 936 people infected. Around 33 percent of those cases appeared in the 21 days leading to Sept 13, the WHO said.

In Liberia, as of Sept 9, 1,296 people had died, which was 54 percent of the 2,407 people infected. Majority, or 1,383 of those cases were recorded in the three weeks before Sept 9.

As of Sept 13 in Sierra Leone, 562 people had died, representing 35 percent of the 1,620 people infected. WHO said 40 percent of those cases were recorded during the preceding 21 days.

Nigeria, as of September 13, had eight deaths already due to Ebola, representing 38 percent of the 21 cases. WHO said six of those cases materialised in the past three weeks.

Valerie Amos, the UN humanitarian chief, said if not dealt with immediately and effectively, Ebola could become a "major humanitarian crisis" in the countries currently affected. She stressed the reality right now in West Africa, Guinea, Sierra Leone and Liberia is already "on the brink of collapse" because these countries can no longer sufficiently provide even the most basic necessities to their respective peoples.

At the rate things are going, the WHO said about $987.8 million is needed for this current Ebola mission. This included health workers' fees, supplies' acquisitions and laboratory works such as tracing people who had been exposed to the virus. While $23.8 million will be needed to pay burial teams and buy body bags.

"We requested about $100 million a month ago and now it is $1 billion, so our ask has gone up 10 times in a month," David Nabarro, the UN's Ebola co-ordinator, said during a briefing in Geneva. "Because of the way the outbreak is advancing, the level of surge we need to do is unprecedented, it is massive."