Africa's first international AIDS conference opens Sunday amid controversy over the cause of the disease and demands that rich countries and companies help the continent most ravaged by the virus.

Researchers, activists and health officials hope the conference will highlight the AIDS disaster in sub-Saharan Africa, where 24.5 million people are infected.

This goal has been sidelined to some extent by a controversy over South African President Thabo Mbeki's interest in so-called AIDS dissidents, some of whom deny that HIV causes AIDS.

But advisers to Mbeki and interested researchers from abroad say they expect Mbeki to lay the debate to rest when he opens the conference Sunday evening.

``As you know, the president likes to write his own speeches...He is putting the final touches to the speech now,'' a presidential spokeswoman said.

A planned news conference by leading scientists to issue a statement declaring that HIV is the cause of AIDS was canceled before Mbeki's scheduled opening address.

Before the opening the Treatment Action Campaign, a South African-based umbrella group backed by 230 AIDS organizations from around the world, marched to demand that pharmaceutical companies make drugs available cheaply to developing nations.

Winnie Mandikizela-Mandela, ex-wife of former South African president Nelson Mandela, fired up the crowd of more than 2,000 demonstrators by demanding the South African government fight HIV-AIDS with the same determination that the liberation struggle used to defeat apartheid.

``If we could struggle against HIV with the same commitment as our struggle against apartheid we can turn back the tide. If we could give the same attention to the struggle against HIV as we did for the bid for the World Cup we could save many lives,'' Mandikizela-Mandela told the crowd.

A minute's silence was also held for the millions that have died from the disease.

Delegates to the conference hope to focus on core issues for the rest of the week -- the social, economic and health disaster of the epidemic.

HIV-AIDS threatens Africa with a development and security crisis, tearing apart the social fabric and economic base of huge swathes of the vast continent.

``Africa is facing an incredible crisis and that crisis is called the AIDS epidemic. It's an unprecedented crisis that required unprecedented responses,'' UNAIDS head Peter Piot told Reuters in an interview.

Piot's comments were echoed by other AIDS experts.

``Never before have countries experienced death rates of this magnitude among young adults of both sexes,'' Helen Rees, chair of South Africa's Medicines Control Council, which licenses drugs, told a pre-conference briefing.

``You can see something like that among men in times of war, when you see a whole generation cut out between 20, 30, 40 years old...the breadwinners, the parents, they are taken out of society by AIDS.''

Rees said African countries would be burdened by millions of orphans, raised without the guidance of parents.

``There are over 12 million children under 15 who lost either mother or both parents to AIDS in Africa,'' she said. ''This is going to increase dramatically over the years, we know for sure.''

One area where researchers hope to make quick progress is in mother-to-child transmission of AIDS. Most infected children caught the virus during birth or while being breastfed, but research shows the rate can be reduced by giving mother and baby drugs around the time of birth.

Durban is in KwaZulu-Natal, the province worst-hit by AIDS in South Africa.

``In this province if you walk into an antenatal clinic, about one woman in three is going to be HIV-infected,'' James McIntyre, director of the perinatal unit at Chris Hani Baragwanath Hospital in Johannesburg, told the briefing.

Zweli Mkhize, Minister of Health for KwaZulu Natal, said education was crucial too. ``We need to remove the feeling of fear where people are so scared of the infection,'' he said. ''Some people actually rape young children because of myths that they might be able to get rid of the infection that way.''

(From Cina Daily)