At Kisiizi hospital in rural south-west Uganda, the working day starts at 0800 with a chapel service for the hospital staff.

Reverend Chris Tugumehabwe, the chaplain of Kisiizi Hospital, then takes off his dog collar and gets changed, ready for his working day running Hope Ministries, a group that seeks to counsel and support Aids victims and their families in this remote and poor part of the country.

After an hour's drive, he reaches the first stop of the day - an Aids sufferer in her late 20s called Erina.

She is lying in a bare mud hut, is clearly very ill and wants privacy from people coming from other villages to see what an Aids sufferer looks like.

Although Uganda has taken a lead in confronting the vast scale of the Aids crisis and the social stigma attached to the disease, Erina's plight is still all too common in a country that was hit early and hard by the Aids pandemic.

An estimated one in ten of the population are HIV-positive and Erina's nine-year-old daughter will soon be another of Uganda's million plus Aids orphans, the highest toll in any country in the world, according to the UN children's fund, Unicef.

Hope Ministries can offer counselling and support to victims like Erina and their families as well as education for the communities. But although there are drugs that can reduce transmission of Aids and mitigate its effects, until now these have been simply too expensive for hospitals and patients in the developing world.

When people have a medical crisis they are faced with huge bills and left impoverished.

In many wards of Kisiizi more than half of all the patients are HIV-positive and the costs of treating Aids and the infections which develop are prohibitive.

Low-cost breakthrough

But a few hundred miles away from Kisiizi, at Makerere University hospital in Uganda's capital, Kampala, there is at last some good news.

Nevirapine reduces the chances of a baby becoming HIV-positive

Last month, the hospital was home to a major breakthrough in preventing the transmission of HIV from mothers to their babies. In the absence of any treatment, HIV-positive women pass on the virus to children in 25% of cases.

When mothers breastfeed their babies, the rate is one-third or higher. The drugs which can prevent transmission have simply been too costly for the developing world.

The study was lead by Professor Frances Miiro.

"What we did was give mothers 200mg of Nevirapine during the onset of labour and also the babies some syrup just after delivery.

"When these babies are followed up we found the transmission rate, compared to cases treated with the drug AZT, was cut by 48%. The total cost of that is about $4 instead of $1,000 per mother-baby pair for the more expensive drugs."

This simple treatment of one pill for the mother and syrup for the new-born baby replaces previous regimes which required several months to implement.

But it is the cost which is most important about this breakthrough, making the prevention of infection at least 20 times less expensive than the drug that unil now has been the cheapest on the market.

And that means that for the first time, countries like Uganda and places like Kisiizi will be able to afford treatment, potentially preventing the infection of up to 400,000 babies every year across the developing world.

A significant step forward?

Frances Miiro explains the likely impact of the new treatment: "The Ugandan minister of health was asked at a press conference whether the government could provide the drug free of charge. He answered: yes, if the drug was acceptable, they would be able to provide it free to women who were ante-natal.

"So you see this is a very good miracle that has come to Africa - and also our friends in Latin America, who also couldn't afford a $1,000 drug. We can afford it and the country, the government can sustain it."

If the results are confirmed there is no doubt that this will be a significant step forward, although the one thing it will not do is reduce the number of children orphaned by the disease.