By Kate Kelland
LONDON (Reuters) - The Bill & Melinda Gates Foundation pledged $50 million (30.86 million pounds) on Wednesday to support emergency efforts to contain West Africa's Ebola epidemic, which has already killed almost 2,300 people in the worst outbreak of the virus in history.
The U.S.-based philanthropic foundation said it would release funds immediately to U.N. agencies and international organisations to help them buy supplies and scale up the emergency response in affected countries.
It will also work with public and private sector partners to speed up to development of drugs, vaccines, and diagnostics that could be effective in treating Ebola patients and preventing further spread of the haemorrhagic fever-causing virus.
"We are working urgently with our partners to identify the most effective ways to help them save lives now and stop transmission of this deadly disease," Sue Desmond-Hellmann, the Foundation's chief executive officer, said in a statement.
Latest data from the World Health Organisation (WHO) show the Ebola outbreak, which began in March, has infected almost 4,300 people so far, killing more than half of them.
The deadly viral infection is raging in three countries - Guinea, Liberia, Sierra Leone - and has also spread into neighbouring Nigeria and Senegal.
The WHO said on Tuesday the Ebola death toll jumped by almost 200 in a single day to at least 2,296 and is already likely to be higher than that. It has previously warned that the epidemic is growing "exponentially" and there could be up to 20,000 cases in West Africa before it is brought to a halt.
Chris Elias, the Gates Foundation's head of global development, said in a telephone interview the group would be assessing over coming days where funds could be best spent.
Some would go to the most acute and immediate needs, he said, and some would be put towards more longer-term research into treatments and ways of preventing future outbreaks.
"The spread of this disease has really happened because of the very weak health systems in these very poor countries," he said. "We need to be thinking how we can build up those health services, how we train healthcare workers, and how we make sure they have the equipment they need to do their jobs."
The Gates money comes after the British government and the Wellcome Trust medical charity last month pledged 6.5 million pounds ($10.8 mln) to speed up research on Ebola, a disease for which there is currently no licensed treatment or vaccine.
The WHO has backed the use of untested drugs, as long as conditions on consent are met, and is hoping for improved supplies of experimental medicines by the end of the year.
Britain's minister for international development, Justine Greening, welcomed the Gates support, saying the "serious health, social and economic risks posed by one of the worst outbreaks of the disease require the entire international community to do more to assist".
The Gates Foundation - set up by the billionaire founder of Microsoft Bill Gates to fight disease and poverty in poor countries - has already committed more than $10 million to fight the Ebola outbreak, including $5 million to the WHO for emergency operations and research and development assessments and $5 million to the U.S. Fund for UNICEF to support efforts in Liberia, Sierra Leone and Guinea.
In its statement, the foundation said it would also give an extra $2 million immediately to the U.S. Centres for Disease Control and Prevention (CDC) to support incident management, treatment, and health care system strengthening.
(Editing by Alison Williams and Ralph Boulton)