It is 5pm, but the shack's female occupants are just stirring and preparing for another hard night. Nana Makhanya, 37, recces the shed from a nearby car as a door creaks open to reveal a bustling black woman with a skinny, defeated-looking friend, her face etched with tribal scars and shoulders so slouched they almost touch.
"I love my work," she says, instructing her colleague, Nchula Nokuthula, to gather up the female condoms. Nonetheless, she needs a cigarette to get started. Ms Makhanya, mother of four, Roman Catholic and sangoma (traditional healer), is a rarity; an expert at cold-calling on KwaZulu-Natal's roadside prostitutes and approaching the truck drivers who use their services.
Ms Nokuthula has been trying for weeks to befriend the women. It has been tough going. "I knew nothing of commercial sex workers before this job," she explains. "In our culture we look down on these women." But Ms Makhanya's help is beginning to pay off. This time Ms Nokuthula is invited into the shack, built by the truck stop's white owner, who charges truckers 10 rand (pounds 1.30) to park overnight and sleep in their lorries. The women, poor and uneducated, are the lure which fills the stop. The going rate is R30 - less than pounds 4 - for sexual intercourse with a condom, R60 without. When times are hard the price may be a bag of sugar.
In the spotlessly clean shed, crammed with six beds, Ms Makhanya demonstrates how to insert a female condom. Mission is accomplished when she makes the women laugh.
Ms Makhanya is toiling in the face of one of the world's worst HIV explosions. Seven years ago, HIV was virtually unknown in KwaZulu-Natal. Now one in four young adults is infected - double the rate for the rest of the country. In the next two years infection is forecast to rise to 40 per cent. With the rest of South Africa on the same curve, the virus will soon devour two per cent of the country's GDP and threatens to break a health system struggling to serve millions of poor blacks for the first time.
Truckers are believed to have played a crucial role in KwaZulu-Natal's epidemic, with thousands of lorries hurtling along the main N2 and N3 highways daily, travelling as far north as Malawi. Ms Makhanya is promoting the use of male and female condoms on these routes, but it is an uphill task. "The truckers say: 'How can you eat a sweet with the wrapper on?' " she says.
Down the N3 in Durban, Dr Gita Ramjee, of the Medical Research Council, says Third World women have no power in a society where men are expected to be unfaithful and women must meet their sexual demands. Dr Ramjee has recruited 150 roadside sex workers to a United Nations project to test a vaginal cream containing Nonoxynol 9, which may protect women from HIV. Her research suggests half the province's prostitutes are infected.
But it is in rural areas, far from the main arterial routes, that the virus is now coming home to roost. In the northern KwaZulu-Natal hills, at the end of a 25-mile dirt road, is the town of Hlabisa.
The town's hospital, manned by 12 British doctors, is preparing for the usual September baby boom, nine months after Hlabisa's migrant workers returned home for Christmas. But with one in four local women proving HIV-positive in antenatal tests, joy is tinged with sadness. As the babies arrive, the young adults begin to succumb to Aids-related illnesses.
Dr David Wilkinson, who started his research in Hlabisa in 1991, describes the local level of HIV infection as "a nightmare". The epidemic is partly driven by the high incidence of untreated sexually transmitted diseases which greatly increase the chances of contracting the virus.
The link with trucking and other migrant labour is not yet proven, but researcher Mark Lurie argues that any such link would be accentuated in South Africa, where apartheid made migrancy a way of life to create a vast pool of cheap black labour. "If you wanted to create an HIV epidemic," he said, "you would take millions of young men away from their homes, house them in single-sex hostels, give them free access to alcohol and commercial sex workers and then, just to make it really sinister, you would send them home once in a while."
If Mr Lurie proves his case he wants the government to take radical steps to focus economic development on rural areas. It must not simply accept that the old system cannot be changed.
The government, meanwhile, has declared the fight against Aids the "new struggle", but the health department lost millions of rand on an Aids awareness play which was never staged, and has yet to launch any large- scale advertising campaign.
In Hlabisa district, Aids awareness is left to a dozen local people who have braved social stigma to "come out" as HIV-positive. A study by Suzanne Leclerc-Madlala, a medical anthropologist at the University of Durban- Westville, suggests this small group faces a terrifying fatalism. She claims that the young people are so convinced they will be wiped out that they are deliberately infecting each other in a "shocking mutation of ubuntu" (African community spirit).
Jabu Shezi, a mother of five and the wife of a truck driver, is one of Hlabisa's dozen pioneers. She displays none of Ms Leclerc-Madlala's nihilism. She tested HIV-positive in 1993, her husband is also infected. In a society where spouses commonly reject carriers of the virus, the couple have stuck together. They know about AZT and expensive Western drugs that can prolong the lives of HIV carriers, but accept they cannot afford them.
So they battle on to raise the paltry funds to stage safe sex plays in local schools. But their task dwarfs them. Dr Wilkinson argues that the Aids epidemic poses "the biggest threat to South Africa, post-apartheid". That seems far too big a crisis to leave to a brave, but underfunded, group of volunteers.