MHLATUZE, Swaziland

We’re now marking the 25th anniversary of the detection of AIDS, and it has been a sad chapter in the history of humanity. It’s been a quarter-century of self-delusion, dithering and failure at every level.

In America, we may think of AIDS as something that is behind us, but this year it will kill almost three million people worldwide. And a new victim is still being infected every eight seconds.

Southern Africa is becoming the land of orphans, kids like Nomzamo Ngubeni, a fifth grader who is now the head of her household.

Nomzamo is 12, a soft-spoken schoolgirl with close-cropped hair here in central Swaziland, the country with the highest H.I.V. infection rate in the world. Two out of five adults here have the virus, and very few get the antiretroviral medicines that can save their lives.

Although Nomzamo probably does not have the virus (although it’s hard to be sure because she’s never been tested for it), her life is entirely framed by the epidemic. Her parents both died of AIDS, so she and her two younger sisters moved in with an aunt — only to find that the aunt was dying of AIDS as well.

Nomzamo nursed the aunt for months and buried her last year. So at the age of 11, she found herself in charge of the family and its thatch-roofed hut, which has no electricity or running water. She is now both mother and father to her little sisters, Nokwanda, 9, and Temhlanga, 7.

She wakes them up in the morning to go to school, and forces them to take their baths and do their homework. She washes their clothes and cuts their hair. She consoles them when they miss their parents. When they misbehave, she beats them. She fetches water and firewood, and in the evenings she cooks for them — if there is food.

“If there is no food, then we just go to sleep with nothing,” Nomzamo explains. “The kids don’t cry. They just go to sleep.”

If all of this seems too much for a 12-year-old, it is. The stress is wearing her down and causing her to do poorly in school.

Like many households in southern Africa, this family no longer has any able-bodied person to till the ground, so the family’s land lies fallow. These sisters get one good meal each day — at school, supplied by the World Food Program — and they beg or borrow the rest.

There are indeed some heroes in the AIDS saga, including American nuns, the Missionaries of the Sacred Heart, known as the Cabrini Sisters (www.cabrinifoundation.org). Nuns like Sister Barbara Staley, originally from Pennsylvania, live in this remote pocket of Swaziland and look after the flotsam of the AIDS crisis. With help from CARE, the sisters shelter and school many of the orphans; they pay the fees that allow Nomzamo and her sisters to attend the public school.

But mostly the last quarter-century of AIDS has been a shameful period of neglect. In the U.S., President Ronald Reagan didn’t let the word “AIDS” slip past his lips in public until 1987. And nobody behaved more immorally than the moralizers, people like Patrick Buchanan, who declared in 1983: “The poor homosexuals — they have declared war against nature, and now nature is exacting an awful retribution.” The Rev. Jerry Falwell put it this way: “AIDS is the wrath of a just God against homosexuals.”

In retrospect, the gross immorality of the 1980’s wasn’t committed in San Francisco bathhouses, but in the corridors of power by self-righteous political and religious leaders whose indifference to the suffering of gays allowed the epidemic to spread.

Misgovernance has been even worse in Africa. South Africa’s president, Thabo Mbeki, refused for years to address AIDS seriously and is probably responsible for more deaths of blacks than any of his white racist predecessors. And here in Swaziland, the playboy king sets a horrendous example of sexual excess by publicly reviewing tens of thousands of bare-breasted teenage virgins so he can choose new wives for his harem.

There are some signs that leaders around the world have finally been waking up to the challenge of AIDS in the last few years. Some countries, like Kenya, Zimbabwe and China, may have turned the corner. President Bush has vastly increased the funds for AIDS in Africa.

But the bottom line remains that for the last 25 years, we’ve faced an enormous public health challenge — one expected to be comparable to the mortality an earlier generation faced from World War II. And in that test, we have disgraced ourselves.

And that is one reason why, in this forgotten part of Swaziland, a 12-year-old looks old beyond her years.