The World Health Organisation says the Ebola infection rate could soon reach 10,000 a week as world leaders prepared to hold talks on the crisis at the United Nations.
WHO assistant director-general Bruce Aylward, describing his figures as a working forecast, said the epidemic "could reach 5000 to 10,000 cases per week by the first week of December".
The latest death toll is 4447, from 8914 recorded infection cases, Aylward said as the worst-ever Ebola outbreak spirals in the three hardest-hit countries of Liberia, Sierra Leone and Guinea.
Governments in west Africa have been scrambling to contain the epidemic, with patients in the Liberian capital describing devastating scenes as patients struggled to survive during a strike by health workers.
A 56-year-old Sudanese doctor who had worked as a UN volunteer in Liberia died of Ebola on Monday night after arriving in Germany last week for treatment.
Outside west Africa, medical staff have also been particularly at risk during the crisis, with at least two cases of contamination reported despite stringent safety protocols.
A nurse in the Texan city of Dallas, Nina Pham, said she was "doing well" after catching the virus while caring for a Liberian Ebola patient, but authorities warned 76 workers may have been exposed during his 10-day stay in the hospital.
Spanish nurse Teresa Romero, 44, is thought to have caught Ebola while treating an elderly missionary who was infected in Sierra Leone and died on September 25.
Liberian health workers late on Tuesday ended a two-day strike to secure risk pay for Ebola, saying they put the needs of their endangered country first following global appeals to end the protest.
George Williams, secretary general of the National workers union of Liberia, said workers had ended the stoppage "first for the love we have for our people, and also because we received calls from everywhere in the world".
A statement from the union said the strike had aimed to call attention to the "neglect, deception, feeble threats and the failure of our government to demonstrate good leadership, foresight and maturity" during the crisis.
Ninety-five Liberian health workers have died so far in the epidemic. Their colleagues want compensation for the risk of dealing with Ebola, which spreads through contact with bodily fluids and for which there is no vaccine or widely available treatment.
In the capital Monrovia, a hospital patient quoted on local radio described scenes of desolation, with sick people climbing over the fence to escape from the treatment unit after being deserted by striking staffers.
"We risk our life every day and the government remains insensible to our plight," said Alphonso Wesseh, a health worker who joined the strike.
"It's not human. One of our colleagues died because he was bitten by a patient," he said. "We are in a hellish situation, so we want to be compensated as a result."
In the US, Facebook co-founder Mark Zuckerberg announced a $US25 million ($A27.05 million) donation to the US Centers for Disease Control Foundation to help efforts to contain the epidemic.
"Grants like this directly help the frontline responders in their heroic work," Zuckerberg said on his Facebook page.
British troops began loading a ship that will set sail for Sierra Leone this week to help in efforts to contain the outbreak.
The civilian-staffed military ship will travel with three helicopters, air crews and engineers to provide transport and support to medical teams and aid workers.
Measures have been introduced in the United States, Canada and Britain to screen for possible Ebola infections among passengers arriving at airports from African countries hit by the virus.
Asian aviation hub Singapore said it would also step up screening at Changi Airport.
The UN nuclear agency said it would send specialised equipment to the west African countries hit by the Ebola outbreak to help faster diagnosis.