The UK has called for urgent decisive action from the international community to deal with the growing Ebola epidemic in West Africa.
Speaking at a conference in London co-hosted with Sierra Leone, UK Foreign Secretary Philip Hammond called for more financial aid, doctors and nurses.
British nurse William Pooley, who contracted Ebola in Sierra Leone, made an emotional appeal for more action.
It is the world's worst outbreak of the virus, killing 3,338 people so far.
There have been 7,178 confirmed cases, with Sierra Leone, Liberia and Guinea suffering the most.
Leading charity Save the Children earlier warned that Ebola was spreading at a "terrifying rate", with the number of new recorded cases doubling every few weeks.
It said that a rate of five new Ebola cases an hour in Sierra Leone meant healthcare demands were far outstripping supply.
'Horror and misery'
Mr Hammond announced plans for a pilot scheme that would involve setting up community health care centres in Sierra Leone to isolate patients at the early stages of infection when Ebola is less contagious.
"The alternative is allowing this disease to progress," said Mr Hammond, citing a worst-case scenario issued by experts that one and a half million people could be infected by January.
The main agenda of the Ebola Donors Conference in London was to discuss what the global community could do to provide an effective international response.
Ministers, diplomats and health experts from about 20 different countries, including the US, France, Japan, Australia and all of the West African nations hit by the disease, were in attendance.
Speaking at the conference, Mr Pooley described his experiences treating a young boy and his sister, who both died from the disease.
"I put her in a bag and left her next to her brother. She was a beautiful little girl. So, my specific fear is that the horror and the misery of these deaths, really fill a well of my despair."
He said he did not know what would happen if what he had witnessed was repeated a million times.
Sierra Leone's President Ernest Bai Koroma was unable to attend the conference at the last minute, but was reported to have participated via video link.
Separately, health officials in Texas say about 80 people are being monitored for symptoms of Ebola, after coming into contact with a Liberian man who is being treated for Ebola in hospital.
About 12-18 people, including five children, had contact with Thomas Eric Duncan, who is in a serious condition.
Meanwhile, UN coordinator for Ebola Anthony Banbury says the disease has now reached every county in Liberia.
He said that more needed to be done to educate remote communities about how to protect themselves from infection.
But Liberian President Ellen Johnson Sirleaf says the situation there is beginning to stabilise, describing warnings of tens of thousands of new cases as "simply wrong", in comments to France 24 on Wednesday.
Earlier this month, Britain said it would build facilities for 700 new beds in Sierra Leone but the first of these will not be ready for weeks, and the rest may take months.
Safety trials for two experimental vaccines are under way in the UK and US, the World Health Organization said on Wednesday, and will be expanded to 10 sites in Africa, Europe and North America in the coming weeks.
It said it expected to begin small-scale use of the experimental vaccines in West Africa early next year.
Ebola virus disease (EVD)
- Symptoms include high fever, bleeding and central nervous system damage
- Spread by body fluids, such as blood and saliva
- Fatality rate can reach 90% - but current outbreak has mortality rate of about 70%
- Incubation period is two to 21 days
- There is no proven vaccine or cure
- Supportive care such as rehydrating patients who have diarrhoea and vomiting can help recovery
- Fruit bats, a delicacy for some West Africans, are considered to be virus's natural host
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