There have been 759 confirmed or suspected cases of the haemorrhagic fever in Guinea, Liberia and Sierra Leone, the World Health Organisation (WHO) said on Tuesday, with 467 people dead.
"This makes the ongoing Ebola outbreak the largest in terms of the number of cases and deaths as well as geographical spread," the WHO said in a statement announcing a two-day conference in Ghana to be attended by 11 West African health ministers.
"Decisions taken at this meeting will be critical in addressing the current and future outbreaks," it said.
Since West Africa's first ever epidemic of the deadly and highly contagious fever broke out in Guinea in January, the WHO has sent in more than 150 experts to help tackle the regional crisis.
Despite the efforts of the UN agency and other health workers, there has been a "significant increase" in the rate of new cases and deaths in recent weeks, the WHO said.
Medical charity Doctors Without Borders (MSF)said last week that the spread of the virus, which has had a mortality rate of up to 90 percent in previous outbreaks, was "out of control", with more than 60 outbreak hotspots.
The Who?s latest figures confirm 129 additional cases of Ebola. There have been 22 new cases and 14 deaths in the past week.
The agency has warned that Ebola could spread to other countries, warning those hardest hit could struggle to contain the disease.
The agency's top Ebola specialist Pierre Formenti told AFP last month that the recent surge in cases had come in part because efforts to contain the virus had been relaxed too quickly after the outbreak appeared to slow down in April.
"One case can restart an entire epidemic," he warned, justifying the dramatic measures taken to contain Ebola, which is spread via bodily fluids including sweat, meaning just touching an infected person is enough to spread the virus.
- Unstoppable bleeding -
Ministers from Guinea, where 413 confirmed, suspected and probable cases have surfaced so far including 303 deaths, and Liberia, which has seen 107 cases and 65 deaths, will take part in the meeting.
Sierra Leone, which has recorded 239 cases and 99 deaths, will also be represented at the conference.
In addition, officials from Ivory Coast, Mali, Senegal, Gambia and Guinea-Bissau, along with Ghana and countries as far afield as Uganda and the Democratic Republic of Congo -- where Ebola was first detected nearly 40 years ago -- have been invited, the WHO said.
They will be joined by a host of UN agencies and other aid organisations including MSF and the Red Cross, as well as personnel from disease control centres in western Africa, the United States, Britain and the European Union.
The WHO has described the current Ebola epidemic as one of the most challenging since the virus was first identified in 1976 in what is now DR Congo.
That outbreak, the deadliest until this year, killed 280 people, according to WHO figures.
Ebola can fell its victims within days, causing severe fever and muscle pain, weakness, vomiting and diarrhoea -- in some cases shutting down organs and causing unstoppable bleeding.
No medicine or vaccine exists for Ebola, which is named after a small river in the DR Congo.