Night falls early along the equator. When darkness creeps across the bay of Santa Ana and sets over the town of Sao Tome, the girls appear in twos or threes, or alone. They wait for clients behind the Farol bar and the Dolores disco, the hubs of evening buzz in the capital of the tiny archipelago of Sao Tome and Principe, which straddles the equator off the coast of Africa.

Around 7 p.m., Angela*, robust and friendly, wearing a black tank top, tight jeans and beads in her short dreadlocks, has just hit the street. Her usual clients are "Portuguese construction workers, sailors from Malabo [Equatorial Guinea], and Saotomese," she tells IRIN/PlusNews.

Her best clients are sailors from the foreign fishing fleets. "They come onshore, hot for wild sex and with gifts of dry fish, rice, clothes and toys," she says. But the Portuguese hold the best promise: "If one fell in love with me, I could leave this life and move to Portugal."

Angela, 28, has a 7-year-old child. She started selling sex at the age of 14, following in her older sister's footsteps. She stopped when she got pregnant and lived with the father of her child until his sudden death three years ago. Her current boyfriend has been in jail for five months, so Angela is back on the streets.

Not for long, she hopes. "I am getting too old, men prefer the young ones. We get wet when it rains, some nights we earn nothing ... not a nice life," she says ruefully.

Growing sex trade

Seroprevalence on the islands is relatively low at 1.5 percent in a population of some 150,000. However, the growing influx of oilmen, sailors and fishermen from neighbouring countries is causing concern, especially considering that half the population is poor, according to the United Nations.

Locals agree that prostitution in the capital has risen the last three years. More girls hang around the streets at night; more men prowl the bars and discos, coming alone and leaving accompanied.

An observant client of some sex workers might notice that they take a condom out of a pretty box crafted from a local precious wood, which means they have been through the sexual health education programme the Italian non-governmental organisation (NGO), Alisei, has been running since 2006.

"The box is something special that says, 'I am special, I take care of myself'," said Alisei coordinator Mariangela Reina.

The diffuse nature of sex work in Sao Tome makes it hard to reach the meninas (girls in Portuguese), as the young sex workers are known, with life-saving, AIDS-preventing information. Alisei has problems recruiting and retaining peer educators.

"The meninas don't want to be associated with sex work or AIDS," said Reina. "It is a hidden phenomenon, and reaching them requires time and patience."

Reina distinguishes between the "mobiles" - the more upmarket sex workers who sell sex occasionally - and the "fixed", or regulars, who are more obvious about what they do and are easier to reach with condoms and information.

Streetwalkers are found only in the capital. Elsewhere, sex work is mainly done out of bars and discos, with the variant of "maritime prostitution", which is tied to the arrival of ships in the capital and the fishing ports.

First ever survey

This year, Alisei, with funding from the Global Fund to Fight AIDS, Malaria and Tuberculosis, interviewed 120 people in the first ever survey of the sex trade in Sao Tome. The information will form the cornerstone of a strategic protection plan for sex workers.

The study found that the overall knowledge of AIDS was high, and nine out of 10 respondents mentioned the male condom as the preferred protection against sexually transmitted infections (STIs) and unwanted pregnancy.

In more than half the sexual encounters both partners had brought condoms. However, mistrustful of men, most women surveyed preferred to use their own. Ten percent reported problems fitting a drunk or older man with a condom.

The women obtain condoms from health posts and NGOs but would like to have them available in shops, bars and discos that are open at night. Worryingly, 17 percent of the women surveyed had agreed to have sex without a condom and 24 percent usually drank alcohol before sex. Roughly half said they did not feel good about earning a living from sex.

Most were aged between 15 and 24, and most of the younger workers viewed commercial sex as temporary until they could find a man or a job or had acquired some possessions.

One-third reported having one client per day; another third had two or more clients per day, and the rest had a variable number of clients daily. Just under half said they had foreign clients, but most clients were local.

In focus groups, the sex workers listed European tourists as the best clients. "They pay in forex, do it faster, are more romantic, and pay for drinks, food and breakfast without discounting it from the total price," said Alisei educator Babica Dias. Prices varied from US$8-10 for a local client to US$20-30 for foreigners.

The Associacao Saotomense de Planejamento Familiar (ASPF), a local NGO, occasionally distributed condoms among customs officers at the capital's harbour, but none in the fishing ports. "We should have programmes there," said Amado Vaz, head of ASPF.

Pink clogs and gold earrings

Tete*, 18, hangs out at a tiny but lively bar near the Alisei office in Sao Tome and rents a room in a nearby house. She wears shocking pink clogs, denim shorts, a white-and-gold top and big gold earrings, and has followed her older sister into the sex trade.

The Alisei staff has gained her trust, and Tete has gained information and condoms. She has tested twice for HIV: "I was afraid," she says.

Alisei's Dias and Dina Zolda Cruz, a peer educator, pursue the meninas with dogged patience and good humour, in spite of their initial reticence and failure to keep appointments. "They are shy, they don't want to talk and don't want to listen," says Dias.

Eventually trust sets in and peer educators teach them negotiating skills. According to Cruz, "The best moment to discuss a condom is once [they are] inside the car, but before sex. The best approach is to emphasise the client's protection."

Equipped with these skills and their pretty boxes, the meninas will be safer when night falls in Sao Tome.

* Not her real name