When AIDS counsellor Nobafunti Dondolo's mobile phone started beeping one Sunday afternoon, she knew someone was in trouble. "It was a message from one of my clients who was very sick," said Dondolo. "She was vomiting blood - the family didn't know what to do."
With a flick of her thumb, Dondolo sent a top priority alert message from her mobile phone to healthcare managers who within seconds dispatched an ambulance to fetch the patient from a rickety shack in this sprawling township near Cape Town.
"She survived," said Dondolo, who is also HIV positive. "This phone makes life so much easier."
Unlike most HIV/AIDS counsellors in South Africa, who toil with pen and paper to keep track of the country's estimated 6.5 million sufferers, Dondolo and her colleagues rely on an easy-to-use text message system.
Specially tailored mobile phones are programmed with a list of questions aimed at monitoring patients on anti-retroviral (ARV) drugs: Is the patient experiencing side effects? Is she eating healthily? Does she have clean water?
During home visits to AIDS sufferers, counsellors ask the questions and immediately text the answers to a database at the University of Cape Town. Doctors and health workers monitor the database and can respond to urgent requests.
Most importantly, counsellors count how many ARV pills are left and forward the details, keeping tabs on whether patients are correctly taking the complex cocktail of drugs and also encouraging them to be rigorous about their medication.
"It is real time," said Jalal Ghiassi-Razavi, project manager. "The carers may not know the situation is critical but the doctors receiving the message might and they can respond. A piece of paper won't be dealt with until following week."
South Africa is struggling with the biggest caseload of HIV sufferers in the world and the government has been accused of doing too little to halt the disease and treat those infected.
Researchers at the University of Cape Town started the text messaging project, called CellLife, in 2000 to harness technology to help tackle one of South Africa's biggest killers.
CellLife works with the Desmond Tutu HIV/AIDS Research Centre and clinic. Around 1,000 patients from Guguletu are logged onto their system.
Patients say the technology makes the process more systematic. Knowing their counsellor is just a text message away is also reassuring.
"At first it was hard to remember to take all my drugs but I knew my counsellor was counting the pills and would come and visit if I was too ill to travel to the clinic," said Eric Makubalo, 35, who discovered he was HIV positive in 1998 and started taking ARV drugs last year.
Makubalo's girlfriend died of AIDS seven years ago after keeping her illness secret for fear of being ostracised. After that Makubalo vowed to help others deal with AIDS and became a counsellor at the Guguletu centre, where he is also a patient.
Only a fraction of those living with HIV in South Africa have access to life-saving ARV drugs and even those who do get the pills sometimes fail to take them as prescribed.
Makubalo's colleague Lindelwa Burns, 32, is also HIV positive but gets her drugs from a different clinic and says she envies patients in Guguletu.
"At my clinic they don't even do home visits they just screen you, give you drugs and leave you to get on with it," she said between coughs. Burns knows from experience that ARVs can cause nasty side effects and says it is tempting to skip pills.
"I know what would happen if I didn't take my ARVs so I take them, but I know I could cheat because no one is checking. I'm sure plenty of patients don't stick to the regime," she said.
CellLife has launched a second site in a remote village in South Africa's rural North West province, and secured funding from pop star Elton John's AIDS foundation to open five more.
The project harnesses the technology of one of Africa's most successful growth sectors - mobile phones. The number of Africans owning a mobile phone has leapt some 1,000 percent in the past five years to about 8 percent of the population.
As well as monitoring individuals, researchers in the CellLife project use data collected by counsellors to track trends and collate valuable information in a field where comparatively little research has been carried out.
"It helps us tell if one particular batch of a drug or one manufacturer is causing problems," said Ghiassi-Razavi. "It is a pity, but Africa is really the testing ground for the fight against AIDS."