LONDON, Oct 2 (Reuters) - Britain made a plea for international help to deal with the world's worst Ebola outbreak at the start of a conference in London on Thursday, with one charity warning that five people are being infected with the virus every hour in Sierra Leone.
Ebola has killed at least 3,338 in West Africa -- mainly in Sierra Leone, Guinea and Liberia -- out of 7,178 cases as of Sept. 28, the World Health Organization (WHO) says, and cases have been recorded elsewhere, including in the United States.
Sierra Leone's president, Ernest Bai Koroma, canceled his attendance at the conference just hours before it started. His plane had had technical problems, Britain's Foreign Office said.
Speaking on Thursday before the "Defeating Ebola" conference began, Britain's Foreign Secretary, Philip Hammond, called for countries to increase financial aid as well as other vital help including medical expertise, transport and supplies.
"We need help from the international community to provide us with the doctors and nurses, so we're asking other countries to piggy back on the structure we've put in place," he said.
"Britain's got a footprint on the ground in Sierra Leone, we've got military engineers there, we've got a big DFID presence, we've got a plan to roll out a large number of additonal Ebola treatment beds," he said.
Although WHO said the total number of new cases had fallen for a second week, it warned of under-reporting and said there were few signs of the epidemic being brought under control.
"Transmission remains persistent and widespread in Guinea, Liberia and Sierra Leone, with strong evidence of increasing case incidence in several districts," WHO said.
The Save the Children charity warned the authorities faced the propsect of an epidemic "spreading like wildfire" across Sierra Leone, saying there had been 765 new cases reported in the country last week but there were only 327 beds available.
"The scale of the Ebola epidemic is devastating and growing every day, with five people infected every hour in Sierra Leone last week," the charity's chief executive, Justin Forsyth, said.
"We need a coordinated international response that ensures treatment centers are built and staffed immediately."
Although the charity praised UK efforts, a British parliamentary committee said on Thursday that cuts in aid from Britain to Libera and Sierra Leone had compromised the fight against the disease.
"In the midst of this devastating epidemic ... it is wrong for the UK to cut its support to these two countries by nearly a fifth," International Development Committee chairman, Malcolm Bruce, said in a report from the committee.
"The planned termination of further UK funding to the Liberian health sector is especially unwise."
DFID said it had promised 120 million pounds ($200 million) towards helping health services in Sierra Leone. (Reporting by Michael Holden; Editing by Louise Ireland)