The BBC's Gareth Jones reports on Aids in KwaZulu Natal

Latest figures issued by the Joint United Nations Programme on HIV/Aids (UNAIDS) and the World Health Organisation paint a grim picture of a disease leaving millions dead around the world.

Experts described almost six million new cases as the world's "collective failure" to deal with the disease.

Although sub-Sahara Africa continues to be the global epicentre of Aids, the research indicates that the disease is rapidly gaining new footholds in Asia and Eastern Europe.

The reseach shows that:

• 33.4m people are known to be living with the infection
• 12m Africans have already died
• Four African countries estimate a quarter of adults carry HIV
• Aids reduced life expectancy by 17 years in worst hit areas

South Africa alone accounts for one out of every seven new infections on the continent.

One in three people aged 15 to 49 has HIV in KwaZulu Natal - one of the highest rates in the world.

Many of the country's infections have come as men in the mostly mining-based economy spend long periods away from home and turn to prostitutes, the report says.

Dr Peter Piot of UNAIDS: "We are not powerless - but we are not doing enough"

In contrast, a number of countries in West Africa remain relatively less affected, in part as a result of early and sustained prevention efforts.

In North America and Western Europe, the availability of new more potent anti-HIV drug combinations has helped people with HIV to live longer and deaths in the US dropped by two-thirds between 1995 and 1997.

However, new HIV infections have remained constant, indicating that preventative programmes are failing.

Children: High risk of HIV infection

Dr Peter Piot, executive director of UNAIDS, said: "Two decades into the Aids epidemic, we know better than ever before about prevention.

"Yet almost six million people became infected this year.

"Every one of these new HIV infections represents a prevention failure, our collective failure."

Economic disaster

In the worst affected countries, Aids life expectancy has plummetted as infant deaths have taken their toll.

In Namibia alone infant mortality is expected to double by 2010.

But while the human cost continues to leave its mark, the onslaught of Aids is also hitting the economic development of the worst affected countries.

Aids is reported to have absorbed one fifth of company earnings in Zimbabwe. Firms in Tanzania and Zambia estimate the cost of Aids illnesses and death was more than their total annual profits.

David Heymann, executive director of the WHO Communicable Diseases Cluster, said: "Aids is a deadly serious public health threat.

"But as the epidemic continues to spin out of control, countries face more than just a health crisis.

"They face a growing threat to human development and to economic and social stability."

War spreads the disease

Conflict has also become a critical factor in the spread of the disease.

In Rwanda, before the political turmoil of the mid-1990s, infection rates were approximately 10% in urban areas and around 1% in the countryside.

Western drugs: Death rates drop but infections continue

By 1997 the urban and rural rate had reached just over 11%. HIV infection rose sixfold among formerly rural people who had fled to refugee camps.

Many carriers have no access to voluntary testing or counselling.

Even when these services are offered, many do not want to know or acknowledge their HIV status because of the blame and shame attached to the disease.

In the Zimbabwe city of Mutare, 40% of pregnant women are thought to be HIV-infected, and probably 30,000 have the disease. Yet the sole HIV support group in the city has just 70 members.

In another study of home-based care schemes in southern Africa, fewer than one in 10 people who were caring for HIV-infected relatives acknowledged that they were suffering from the disease.

Dr Piot said: "One might think that in a country with a quarter or third of the population infected, people would become more open about the epidemic.

"Experience teaches us that this does not happen automatically.