It was too terrible a word to utter so, as the sickness spread, the township took refuge in euphemisms. Skinny, coughing residents were said to have won the lottery, or opened a bank account, or acquired a four-by-four vehicle; darkly ironic ways of stating what they really had - Aids.

For years Khayelitsha, a sprawl of wooden and corrugated tin shacks outside Cape Town, did not name the disease outright. It was too shameful, too frightening. To have HIV, the virus which causes Aids, was to be a plague carrier who had slept around and would soon die. Admit to having it and you risked becoming a pariah abandoned by your partner, evicted from your home and shunned by your community.

Most declined to be tested, preferring ignorance about their status even if it meant missing treatment and infecting others. In such a climate the killer was not so much HIV but stigma.

Today the atmosphere is transformed. The disease is still wreaking devastation, and stigma endures, but there is an openness which has galvanised treatment efforts.

"People used to skulk outside, waiting until the coast was clear before coming in," said Nosipho Tyhomfa, a counsellor at one of the three Médecins sans Frontières HIV clinics in Khayelitsha. "Now they are much more relaxed."

Of the township's 500,000 residents 42% have come forward for testing - almost seven times the national average, MSF estimates. "It's getting better and better," said Sindiso Tutu, a youth centre nurse. Clinics which were near deserted just a few years ago, despite the fact that more than 50,000 residents were estimated to have HIV, are now packed with people coming in for testing and treatment.

Michael Hamnca, 38, had to quit his job as a shopping centre guard when his weight fell to 45kg. Coughing, barely able to walk, his friends thought it was his "last days", he said. Following a cousin's lead, the father of three took an HIV test in July and started a course of antiretroviral drugs in September. He has since gained 10kg. "My friends said I am coming back." They did not recoil when told it was thanks to Aids drugs, he said. "Some are afraid to get tested but I said it was better to be open."

Ntombekhaya Nongogo, 28, an 11-month-old daughter cradled in her lap, said she too had been open since starting treatment. "I feel better. Why shouldn't I tell people?"

Both were emboldened by weekly group counselling sessions for those starting treatment. For the first hour a counsellor reiterates the importance of nutrition, of taking the two pills every morning and evening and of coping with side-effects. The second hour is a free-wheeling discussion which often focuses on disclosure - how and when to tell relatives, friends and partners about being HIV positive. The sessions are not downbeat: tales of suspicious siblings and runaway boyfriends are greeted with laughter, sympathy and advice.

Several reasons explain the erosion in stigma, which reached a nadir in 1998 when a mob beat a woman to death after she admitted on television that she had HIV. Awareness campaigns have blitzed billboards, newspapers, radio and television with the message that the virus is not restricted to gay people or prostitutes. Nelson Mandela and Mangosuthu Buthelezi, among others, have spoken of losing relatives. Activists proclaim their HIV positive status on T-shirts and at rallies. A national household survey found that more than 90% were willing to care for an infected relative. Nearly half of those aged 15 and older found nothing wrong with marrying and having sex with an HIV-positive person.

Khayelitsha has progressed further thanks to antiretrovirals - provided free by MSF and the provincial government - which can extend life for years, even decades, thus weakening the association with death. But stigma is far from vanquished. At funerals, grieving relatives usually insist that the cause of death was a related illness such as tuberculosis.