CAPE TOWN, South Africa — Laura Bush, clearly moved Tuesday by a song from a roomful of HIV-positive mothers, thanked them for “stripping away the stigma” of AIDS and helping prevent more babies in their impoverished township from being born with the disease.

Mrs. Bush, on a three-nation African trip that aims to highlight the Bush administration’s battle against AIDS on the world’s poorest continent, visited a health complex set amid thousands of tin shacks with tar paper roofs held down by tires in the Khayelitsha area outside Cape Town.

About 400 women deliver babies at the facility each month. Though 28 percent of them have the virus that causes AIDS, treatment at the facility has reduced the transmission of the disease to their newborns to under 5 percent, said Dr. Keith Cloete, health director for the Western Cape province.

Mrs. Bush was at the Khayelitsha Maternity Obstetrics Unit to showcase work done there through The Mothers’ Programmes, a private organization that receives some assistance through President Bush’s five-year, $15 billion anti-AIDS effort. The program enlists mothers who have kept from transmitting the disease to their own children to mentor new expectant mothers.

A great challenge in the battle against AIDS in Africa is persuading the many people who are leery of talking about the disease to get tested and to take steps to prevent its spread. The first lady met with a few women who told of becoming HIV-positive and of how their enrollment in the program has changed their lives and those of others for the better.

She then went to an outer room, where she was greeted by women singing in their native language of Xhosa a song offering thanks for her visit and for America’s help.

About a half dozen women — one wearing a T-shirt with a huge orange HIV-positive logo, another with a baby strapped to her back with a towel — were weaving colorful beads into lanyards as part of an effort to generate extra income for the mostly unwed and unemployed women.

Mrs. Bush informed them, to much laughter, that her White House staff hangs their security credentials from lanyards made through their program.

“This has been very neat, very impressive,” Mrs. Bush told them, choking up a bit as she spoke.

Later, at a speech in Cape Town, Mrs. Bush heralded their work in more detail.

“Today people are learning how to live with AIDS, rather than prepare to die from it. More people are getting tested, and they’re revealing their diagnosis,” she said at the Centre for the Book, a part of the National Library of South Africa that promotes indigenous writing and helps develop a culture of reading. “Through their courage, they’re breaking down stereotypes and stripping the stigma that is often attached to AIDS.”

At the library, Mrs. Bush held a discussion with women from several South African groups fighting against rape and domestic violence, praising efforts to give often-disenfranchised girls the skills to negotiate safe sexual lives and to instill in men the responsibility to respect women.

“I like it that you’re not leaving the men out,” she said.

Mrs. Bush was advertising a new initiative, unveiled earlier this month by her husband, to provide legal protections for African women victimized by violence and sexual abuse. The president said he wants $55 million over three years for that effort.

Addressing domestic violence is a key part of battling the AIDS crisis in South Africa, which has more people infected with HIV than any other country, and across the continent, Mrs. Bush said. Many African women become infected with the disease because their husbands have unprotected sex with others and then force sex on them.

“Violence against women is an outrage that afflicts every society,” she said. “All people have the responsibility to stop the abuse of women wherever it occurs.”

The first lady continues her trip through Africa by flying Wednesday to Tanzania. After a visit to Rwanda, she heads back to Washington on Friday.