The director of the US Centers for Disease Control and Prevention (CDC), Dr. Thomas Frieden, said on Tuesday that some mistakes had been made that might have led to a nurse contracting Ebola from one of her patients.

Frieden said that the CDC would adopt a policy of deploying rapid response teams to assist at hospitals where patients are being treated. He admitted that, had one been sent to the Dallas Hospital where Liberian national Thomas Eric Duncan was being treated in late September, then 26-year-old nurse Nina Pham might not have contracted the disease.

"I wish we had put a team like this on the ground the day the first patient was diagnosed ... but we will do that from today onward with any case in the US," said Frieden.

"We will be there, hands on, within hours, helping hospitals with the situation if there is another case," he said.

Duncan, who had been visiting the US to see family, died of the disease. Pham is still being treated in hospital.

Health authorities say the principal outbreak in West Africa is the worst on record. In the Democratic Republic of Congo, an unrelated outbreak has killed more than 40 people.

Video conference planned

US President Barack Obama said on Tuesday that "the world as a whole is not doing enough" to combat Ebola.

Obama was scheduled to hold a video conference on Wednesday to discuss the Ebola epidemic with the British, French, German and Italian heads of government, alongside other pressing issues such as Syria.

West Africa could see up to 10,000 new Ebola cases a week within two months, the World Health Organization said on Tuesday.

The UN health agency said the Ebola epidemic was still spreading in Guinea, Sierra Leone and Liberia and warned the number of cases will exceed 9,000 this week.

Assistant Director General Bruce Aylward told a press conference at the WHO headquarters in Geneva that the death toll had passed 4,400 from a total of more than 8,900 cases since the outbreak started in Guinea in March.

Even though there were signs that rates of infection were slowing in some of the worst-hit areas, it would be "really, really premature" to read success into the operation to stop the spread of the disease, he continued.

rc/kms (AFP, AP, dpa, Reuters)