Siama heard about MSF at the end of 2002, during MSF's campaign for World AIDS Day in Kenya. Pretending that it was her sister infected with the virus, Siama made enquiries and learnt that MSF offered care and treatment free of charge. The following month, she was registered in the MSF programme and participated in a support group for the first time.

One-o-clock in the morning in the village of Gatwekera, Kibera. Men and women enter in ones and twos into the area around the HIV/AIDS dispensary run by Médecins Sans Frontières (MSF). Dressed in coloured t-shirts emblazoned with the slogan "I know, do you?", there are soon around 40 people gathered next to the church a few metres away. A young woman, smiling and confident, runs the meeting from the middle of the group.

Siama Musine is 30 years old. Like all those present, she is infected with HIV/AIDS and registered in the MSF programme. Siama is a member of MSF's Information, Education and Communication (IEC) team and coordinates the work on treatment literacy (informing people about treatment) in the Kibera slum.

This morning they travelled all over the slum in small groups informing the different communities about HIV/AIDS, the free services offered by MSF, the prevention of sexually transmissible infections (STIs) and so on.

"I have a very pragmatic approach," confides Siama. "I know what I am talking about because I have physically been through it. It is not just something I have read in books."

Siama was a 22 year old apprentice hairdresser when she was infected by her boyfriend of the time. It was in 1997. Despite a positive test result, Siama refused to believe that she was seropositive.

"For years I denied the fact that I was infected with HIV/AIDS. I was "in denial". I told myself that the testing machines did not work properly." But in 2002, Siama's health went downhill, she contracted tuberculosis and became seriously weakened.

Siama heard about MSF at the end of 2002, during MSF's campaign for World AIDS Day in Kenya. Pretending that it was her sister infected with the virus, Siama made enquiries and learnt that MSF offered care and treatment free of charge. The following month, she was registered in the MSF programme and participated in a support group for the first time.

"This was when I finally accepted myself as I was. A lot of people were sharing their experiences so I opened myself up to them."

Encouraged by the MSF team, Siama decided to create a support group herself: KOPLWA, the Kenyan Organisation of People Living with AIDS. Its members meet up every two weeks to share what they are going through, to discuss AIDS prevention and to help people "in denial" accept the virus.

But Siama became weaker and weaker as her health continued to go downhill. Followed up by MSF, she learnt that her CD4 level - which indicates the condition of the immune system - was only at 50. She had to start ARV treatment.

"It was April 4th 2004. I was all skin and bone. Today, you can see that I'm nice and fat again! I have never had side effects and I've recovered my previous form. I don't suffer from opportunistic infections any more and society recognises me as a person again, not just a virus."

To the point where she obtained a visa for South Africa in 2004, when Siama was invited to follow a training course on 'Informing on Treatment' given by the MSF project team in Cape Town. She still wears the course t-shirt like a trophy. She returned to Kenya metamorphosed, totally committed the fight against HIV/AIDS. In January 2004, she launched a programme for MSF in Kibera on "treatment literacy" for people infected with the virus.

"Since I found out that I have the virus, I have lost all my old friends," confides Siama, her hair covered by an elegant Muslim veil. But I have made others, who share their experiences with me and help me reach my goals."

Undoubtedly, one of her goals is to convince the leaders of her Muslim community to accept the reality of HIV/AIDS. "I tell them 'I am young, sexually active. Am I going to infect people?' We all concluded that promoting condoms is necessary."

A committed militant, Siama was also involved in the mobilisation for free treatment during World AIDS Day 2004 and was in front of the Indian embassy in Nairobi when the Delhi government was preparing to vote on controversial legislation on patents and medicines.

She has already notched up some serious victories. Following the pressure applied by different organisations, the prices of ARVs administered by the Kenyan Ministry of Health have dropped to 50 shillings (around 50 eurocents) a month.

"Sometimes people don't want to believe that I have HIV/AIDS, for the simple reason that I am in good health. But I tell them that living with HIV is not a death sentence. It is just a new life that starts."