The South African government is giving free anti-retroviral drugs to some 40,000 HIV positive people, some of whom are now able to plan a future.
Anti-retroviral drugs helped Prudence gain five stone in weight
On this day a year ago, a young woman lay dying, in a cold and spartan house, in a village in South Africa's remote Eastern Cape province.
Aids had eaten into her body. She weighed less than four-and-a-half stone (28.5kg).
Her limbs ached so much that she could barely leave her bed. Her mouth was infected with the thrush that makes it agonising to swallow food.
Her name was Prudence Radebe and she was resigned to her fate.
Today, Prudence is still alive. In fact, she is so full of life that it is hard to believe just how sick she was.
Her weight has shot back up, to nine-and-a-half stone. Her skin is smooth and shiny. She carries buckets of water from the well up the hill with no difficulty.
And, every so often, she likes to do stretching exercises on the little patch of land behind her house.
Prudence knows why she is still alive. "Anti-retroviral drugs saved my life," she says, matter-of-factly.
Fluke of geography
I first met her in September 2004, when she started taking anti-retrovirals. Since then, I have been travelling down to the Eastern Cape every two months to follow her progress.
We do a lot of Aids stories in this part of the world but not many like this... with a happy ending.
It is estimated that five million people are HIV positive in S Africa
Prudence is a clever, cheerful person, with a loving family.
Her recovery leaves me with a warm feeling. It shows there is hope amid the dark, overwhelming despair of the Aids pandemic.
Prudence is, above all, lucky.
She heard that the charity Medecins Sans Frontieres had started an anti-retroviral project in a nearby town and she applied for treatment.
A fluke of geography, if you like.
There are almost one million HIV positive people in the Eastern Cape, and only 4,000 are receiving free anti-retrovirals.
Haunted by death
But Prudence is not just lucky. She had to convince the doctors that she was serious and dedicated. She had to learn about all the complexities of the drugs which she now needs to take every single day for the rest of her life.
She discovered that she might build up resistance if she does not take them properly, and that they can have painful side-effects.
Today she has the zeal of a convert and her language is peppered with the words and terminology of Aids treatment: CD4 count, viral-load, voluntary testing, nevirapine.
If Prudence took you round her village, you would realise just how fortunate she is.
This is one of the most beautiful parts of South Africa. Thatched huts cling to the steep, green hillsides, and children's voices echo across the valleys.
But it is a landscape that is haunted by death.
Prudence is surrounded by tragedy.
I feared the worst for her neighbour, Nontandozela, who had been in bed for the past six months, too weak to stand.
More than 300,000 HIV positive Africans are now on anti-retrovirals
Nontandozela's sister, Victoria, was also sick and lying on the other side of the room.
Four months ago Victoria died.
Nontandozela's daughters watched all this in silence. Their faces betrayed no emotions, but I could not imagine their fear and despair.
The men in the family - the fathers of these young girls - have drifted away.
Nobody knows how to contact them. And nobody has enough money to pay for a taxi to take Nontandozela to the clinic where Prudence started her treatment.
If nothing happens, Nontandozela's days are numbered.
Another young woman with Aids, Lulama, lived further down the valley.
We went to see her in September. She was so weak she could barely speak, let alone leave her squalid bedroom.
In a rasping whisper she said she was worried about her two young boys, aged six and two.
Lulama did not even know what anti-retrovirals were, let alone how she could get them.
Aids is no longer an automatic death sentence in Africa
We got a phone call four days after we got back to Johannesburg.
Lulama had died.
I learnt later that an aunt took those two boys and is doing her best to raise them in a tiny shack in a grim township on the edge of the nearest big city, Durban.
Anti-retrovirals are not miracle drugs but they can keep you alive and healthy for many years, provided you eat well and look after yourself. They buy you time.
Today Prudence is looking to the future, impatient to go back to work in Durban and making plans with her son.
Breaking the cycle
The World Health Organization would like to have three million people in developing countries on anti-retrovirals by the end of this year.
It will not reach that target. It probably will not get anywhere near. But the fact is that something has changed in the Aids pandemic.
More than 300,000 HIV positive Africans are now on anti-retrovirals.
It is not much compared to the total infected population, but Aids is no longer an automatic death sentence in Africa.
After 20 years we are beginning to break the cycle of despair, and that is the significance of Prudence's story.
From Our Own Correspondent was broadcast on Saturday, 14 May, 2005 at 1100 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.