02/05/2013 08:14 BST | Updated 01/07/2013 06:12 BST

The UK Can Bend the Curve of the HIV, TB and Malaria Epidemics

Maurine Murenga's father knew that he was dying of tuberculosis, but with no way of getting the treatment that could have saved him, there was little he could do.

"There is nothing sadder than sitting there, waiting for someone to die," Maurine quietly told a group of parliamentarians in London earlier this week. After her father's death, Maurine was also diagnosed with HIV, along with her baby son.

"It was a very sad time," said Maurine, whose organisation Lean On Me supports young women living with HIV in Kenya. "So many of my friends died, and some committed suicide because they didn't want to end up bedridden. I remember sitting with my son on the balcony, wondering which of us would go first. Then the Global Fund came, and here I am."

By rolling out medicines for HIV and TB and bed nets which help to prevent malaria, the Global Fund to fight AIDS, TB and Malaria has saved the lives of nearly nine million people over the last decade - people like Maurine and her little boy.

"Now I am strong!" her son says, in a film produced by Here I Am, a campaign led by people who have survived HIV, TB and malaria thanks to Global Fund supported programmes. Maurine is a Here I Am ambassador and has travelled from Kenya to ask the UK government to make an early funding announcement ahead of the Global Fund Replenishment Conference in the autumn.

The Global Fund was created by G8 countries in 2002, and currently provides over half of all HIV treatment globally, four fifths of all international assistance to fight TB and 60 per cent of international malaria funding. With over a decade of impact behind it and bolstered by recent scientific and research advances, the Fund can now go even further and could actually bend the curve of the HIV, TB and malaria epidemics, but it needs the continued support of G8 countries like the UK and the US.

While the UK government scored the Global Fund highly in its 2011 review of multilateral aid organisations, it also identified changes that needed to be made to further increase the Fund's impact. As Chair of the Global Fund Board, the UK then led a major transformation of the Fund's funding and accountability mechanisms. I have represented developed country NGOs on the board of the Global Fund for the last two years and seen firsthand how it has evolved to become an organisation of the 21st century.

Two weeks ago President Obama included $1.65 billion for the Global Fund in his 2014 budget request - a tremendous vote of confidence. However under federal law the US is limited to providing no more than one third of total Global Fund financing, so other donors will have to commit $3.3 billion for the same period in order for the Fund to access the full US pledge. It is therefore critical that the UK announces an increase in its contribution and does it well in advance of the autumn replenishment. By doing so, the UK will help to leverage larger pledges from other countries and to maximise potential funding from the US. My organisation, the International HIV/AIDS Alliance, and our partners are calling for a doubling from the current level of £500 million over the period 2011-2013 up to £1 billion over the next three years.

Some donors may be tempted to delay investing in fighting HIV, TB and malaria until the economic situation improves. In reality, this is a false economy. The three diseases already carry a high cost both in human and financial terms, and if we don't grab the opportunity to defeat them, the costs will only increase. In countries like Uganda new HIV infections are already increasing, while multidrug-resistant TB is becoming more widespread around the world, especially in Eastern Europe. If we reduce investments in malaria, a whole generation of children who have never developed resistance could die. If the tools we had for preventing HIV, TB and malaria were fool-proof we could afford to wait, but they are not. All of the science we have - HIV treatment as prevention, pre-exposure prophylaxis, male circumcision, existing TB medicines, insecticide room spraying and use of bed nets - is only partially effective, and to take advantage of it we need to act now, using the resources and systems that have already been put in place. This is a once-in-a-lifetime chance.

The G8 summit at Lough Erne is approaching. In 2005, when Tony Blair hosted this meeting, G8 leaders made an historic promise to work towards universal access to HIV treatment and help African countries to scale up action against malaria. These pledges, which enjoyed cross-party and widespread public support, have helped to fundamentally change the global HIV and malaria response. Today some eight million people are benefiting from antiretroviral drugs and malaria deaths in Africa have been cut by 30 percent between 2005 and 2010.

David Cameron has identified other priorities for this summit - trade, tax and transparency - and will host a pre-meeting focused on world hunger. These are all vital issues, but the Prime Minister also needs to protect what has already been achieved and should encourage the G8 to deliver on past promises. As Maurine Murenga put it to Parliamentary Under Secretary of State for International Development Lynne Featherstone: "If we stop now, we may lose the gains we have made. A luta continua. The struggle must continue in the spirit of saving lives."