Africa's poverty is "a scar on the conscience of the world", UK Prime Minister Tony Blair has told the World Economic Forum in Davos, Switzerland.
U2 singer Bono (right) joined Mr Blair to plead Africa's case
He criticised global leaders for neglecting Africa, saying there would be an outcry if another part of the world was to suffer similar problems.
He appealed for more aid for Africa and said the UK would fund nearly one sixth of a World Health Organisation appeal.
Tackling the spread of HIV has already emerged as a central theme of the week.
Mr Blair was flanked by pop singer Bono and Microsoft founder Bill Gates, the world's richest man, who earlier in the week gave $750m (£400m) to a global programme to vaccinate children against deadly diseases.
He launched his appeal for Africa by stressing the need to tackle diseases that cripple poor countries economically.
"If what [is] happening in Africa today... was happening in any other part of the world there would be such a scandal and clamour that governments would be falling over themselves to do something about this," he said.
Mr Blair has made it clear he wants to use the UK's presidency of the G7 group of rich nations this year to ensure Africa's problems do not slip out of the international spotlight.
TACKLING AFRICA'S POVERTY
The only continent to get poorer since 1979
Nearly 50% of Africans live on less than $1 a day
34% are malnourished
6,000 Aids deaths a day
Source: World Bank, IMF, WHO
More aid is needed, as well as a "very clear mechanism" to avoid donor nations backsliding, he said. He committed the UK to supply £45m ($85m) towards a WHO disease control appeal totalling £300m.
Mr Gates called Africa's poverty and the deaths of "millions of people" due to insufficient research into diseases of poverty "the most scandalous issue of our time".
U2 singer Bono praised both men for "getting it right", and told Mr Blair that helping Africa offered "the chance to touch more people's lives than anything else he can do as prime minister".
He also paid tribute to Mr Gates, saying: "No single man on the planet has done more to impact poverty."
Their appeal was followed by a conference session that included ex-US president Bill Clinton and South Africa's president Thabo Mbeki.
Davos is best known as the top-notch business leaders' networking session, with bosses of more than a fifth of the world's 500 largest companies in attendance.
In Porto Alegre, anti-globalisation protesters hold a rival conference
Economics remains the focus and Thursday's agenda includes discussion on "Spotting the next bubble before it bursts".
Other topics covered include the spread of biological weapons, trade links between the US and Europe, and Argentina's offer to restructure its debt.
More than 20 other world leaders are due to attend the Davos meeting, including Ukraine's new president, Viktor Yushchenko and newly-elected Palestinian leader Mahmoud Abbas.
The rival World Social Forum - the so-called "anti-Davos" for campaigners against globalisation, for fair trade, and many other causes - is also entering its second day, in the Brazilian resort of Porto Alegre.
Brazil's president Lula da Silva is to launch a Global Call to Action Against Poverty there on Thursday.