The BBC's Jeremy Vine on the South African Aids epidemic

On the eve of World Aids Day, Peter Piot, director of UNAIDS, the UN Aids agency, said the region was facing an unprecedented crisis from the disease.

More than 1.5 million people were infected by HIV in southern Africa this year and over half of these infections took place in South Africa alone.

Dr Piot said the epidemic would increasingly be felt at an economic level and could threaten the stability of South Africa, the region's economic powerhouse.

"Hard-won gains in terms of health are going to be wiped out," he said.

"The worst affected countries in the world are in this region."

Archibishop Desmond Tutu of South Africa has urged the world to tackle Aids with the same committment that it tackled apartheid.

Archbishop Tutu said governments should cut their defence budgets by a small percentage so that they can spend more on affordable health care, Aids research and education.

He said that, even though Africa had been hardest hit by the disease, Aids knew no boundaries and was also affecting Asia and Europe.

Africa worst hit

Sub-Saharan Africa accounts for over 22 million of the 33.4 million people infected with HIV around the world.

Some countries in southern Africa have been particularly badly hit, with a fifth of the adult population of Botswana, Namibia, Swaziland and Zimbabwe having the virus that leads to Aids.

Geraldine Fraser-Moleketi, South Africa's welfare minister, said that within three years nearly 250,000 South Africans would die of Aids every year.

This number will rise to half-a-million a year by 2007/8, she added.

More than 1,500 new infections are already taking place every day, and by the end of the first decade of the new millennium more than a quarter of the population is expected to have contracted HIV.

In the next 10 years, average life expectancy in South Africa will drop 20 years, from around 68 to just 48.

The South African Government has announced a $14m campaign to raise awareness about the disease amid growing concerns about the health and economic effect its spread is likely to have on the country's future.

However, controversially, the government refused to pay for prescription of the drug AZT which has proved effective in limiting the spread of HIV.