Global funding for malaria is less than half the $4.9 billion needed in 2010 to prevent and treat the disease that kills around 850,000 people a year, a study showed on Saturday.

Researchers writing in The Lancet medical journal said that 21 countries -- including 12 in Africa -- now get enough or nearly enough donor help to control disease.

However, 50 countries where most people at risk of the disease live do not get enough funding to fight malaria.

'Our analysis identified 10 African countries and five in Asia that are short of necessary funds and have low domestic income,' said Bob Snow of the geographic medicine centre at the Kenya Medical Research Institute in Nairobi, who led the study.

The researchers assessed the level of malaria risk for 93 countries where the disease is endemic and calculated the financial requirements to control it.

They found that international financing for malaria control has risen to $1.94 billion this year from $0.73 billion in 2007.

The Roll Back Malaria advocacy group estimates $4.9 billion is needed in 2010 to adequately control malaria.

According to the World Health Organisation, about 3.3 billion people -- half of the world's population -- are at risk of malaria, which is spread by mosquitoes.

There are about 250 million malaria cases and almost a million malaria deaths each year. People living in the poorest regions are most vulnerable. – Reuters