Geneva: The Ebola epidemic is set to explode unless the response is radically intensified, the WHO said on Tuesday, warning that hundreds of thousands could be infected by the end of the year.
The UN agency said in a report that new cases would surge from hundreds each week to thousands without "drastic improvements in control measures", with the number of infections set to more than triple to 20,000 by November.
"We've rather modestly only extended the projections to November 2, but if you go to... January 2, you're into hundreds of thousands," said Christopher Dye, the head of strategy at the World Health Organization and a co-author of the study.
The research paper warns that the outbreak could drag out for years and become entrenched in west Africa, which has already seen almost 3,000 deaths.
The epidemic might simply "rumble on as it has for the last few months for the next few years," Dye said, adding that "the fear is that Ebola will become more or less a permanent feature of the human population".
Liberia, the hardest-hit nation, has seen 3,000 cases of Ebola and almost 1,600 deaths, with health workers turning people away from treatment units due to chronic shortages of beds and staff.
The country has some 150 foreign specialised medical workers on the ground but the UN has said they need at least 600, and health authorities are aiming to scale its current 400 Ebola beds up to around 2,000 within weeks.
Its response has been bolstered by a US military mission, already being deployed, which will see 3,000 troops providing training and logistics.
But Antonio Vigilante, UN deputy special representative for recovery and governance in Liberia, likened the struggle to "trying to remedy an earthquake when it is happening".
Liberia said today the slow international response risked allowing the country to slide back into civil war alongside neighbouring Sierra Leone, and could reignite civil unrest in Guinea.
"The world cannot wait for Liberia, Sierra Leone and Guinea to slip back into conflict, which could be the result of this slowness in response," Information Minister Lewis Brown told AFP late yesterday.
Sierra Leone, where more than 1,800 have been infected and nearly 600 have died, reported "an overflow of bodies" after a nationwide curfew helped uncover more than 200 new cases.