* Public-private Global Fund fights AIDS, TB and malaria
* Donors due to meet in late 2013 to replenish funds
* Fund director says investment now will avert huge costs
By Kate Kelland
LONDON, Sept 12 (Reuters) - The world's biggest funder of the fight against AIDS, tuberculosis (TB) and malaria said on Thursday it needs $15 billion over the next three years to begin bringing "the three big global pandemics" under control.
In a report released ahead of a pledging conference later this year, the Global Fund to Fight AIDS, TB and Malaria said timely investments could avert $47 billion in extra treatment costs and save millions of lives, but warned that acting too late would mean missing important opportunities.
"The cost of inaction is far greater than the cost of action, from both a moral and an economic perspective," Joanne Carter, head of the RESULTS Educational Fund in the United States and a former Global Fund board member, told reporters.
"We are at the tipping point in the fight against HIV, TB and malaria. If we invest ambitiously now we can save millions of lives and literally defeat these diseases in our lifetime."
The public-private Global Fund, based in Geneva, accounts for around a quarter of international financing to fight HIV and AIDS, and the majority of global funds to fight TB and malaria.
Founded in 2002, the fund raises money from donors every three years and in 2010 secured just under $12 billion for the years 2011 to 2013.
According to the World Health Organisation, malaria infected some 219 million people in 2010, killing around 660,000 of them. Robust figures are, however, hard to establish and other health experts say the annual malaria death toll could be double that.
Some 34 million people were living with the human immunodeficiency virus (HIV) that causes AIDS at the end of 2011, while deaths from AIDS fell to 1.7 million that year from a peak of 2.3 million in 2005.
The Global Fund says that of the estimated 9 million cases of TB worldwide in 2012, only 6 million were diagnosed and treated - leaving an estimated 3 million people with TB who went undiagnosed, untreated or unreported.
International health experts say the tools, medicines and expertise already exist to be able to all but end these three infectious diseases, but say it is a battle to keep up funding levels in a tough global economic climate.
"There are three compelling factors that make this a unique opportunity to fight and defeat these diseases," said Mark Dybul, the Global Funds' executive director.
"We have the experience to know how to fight them effectively, we have new scientific tools, and we understand the epidemiology of these diseases better than ever. We can make a transformative difference, and if we do not act now, the costs will be staggering."
If international donors fail to stump up the at least $15 billion needed, Dybul said this could lead to millions of avoidable cases of HIV during the funding period of 2014 to 2016, which over these patients lifetimes would add up to $47 billion of treatment costs.
Some 3 million fewer people would be treated for TB, and a million lives would be unnecessarily lost because of that, he said, and in malaria the consequences of inadequate funding would be 196,000 lives lost per year and 430 million malaria cases that could have been prevented.
The lion's share of the funding for the Global Fund comes from OECD governments. Private sector entities such as the Bill and Melinda Gates Foundation and Coca-Cola also contribute financially and with services. (Editing by Sonya Hepinstall)