In a market square just outside the town of Kassala, near the border with Eritrea in eastern Sudan, every plastic chair is filled and there is standing room only when the two men come on stage to perform their songs and skits about HIV and AIDS.

In much of the African continent such events have become commonplace, but they are still a novelty in this region of Sudan, where people have only really begun to talk about AIDS in the last few years.

The event was a first for audience member Yassir Musa, 29, who also inspected the informational display set up in a tent near the stage. "Before this, I just knew people should avoid sexual contact outside marriage," he said. He said he knew nothing about condoms.

Another audience member, Ali Awad El Karim, 55, said he believed people become infected with HIV because of illiteracy. He knew about condoms, but did not approve of them. "Condoms themselves can transmit HIV," he said, adding that people could also get HIV from sharing toothbrushes.

One old man in a traditional white turban and jalabia pushed his way out of the small crowd gathering in the tent: "I don't know anything and I don't want to know," he said.

Such attitudes and the low level of knowledge about HIV/AIDS were not surprising, said Connie Shealy, an HIV advisor with GOAL, an international humanitarian organisation running an HIV programme in Kassala. "Sudan is where a lot of countries were 10 years ago." Although the resources and government assistance allocated to AIDS efforts has increased in recent years, she said, "we can't go in with guns blazing."

Condom distribution, for example, a routine element of AIDS awareness events in most countries, would not take place at the market. In fact, condoms were unlikely to be mentioned.

In this region, conservative even by the standards of a country governed by sharia (Islamic law), talking about condoms is viewed by many as tantamount to encouraging "illegal" sexual activity. According to Inas Mubarak, assistant HIV coordinator with GOAL, information about condoms is only given at training workshops for peer educators, who are drawn from high-risk groups like students, soldiers and policemen.

Even after training, some peer educators have difficulty talking about sexual modes of transmission and are ambivalent about condoms. Mohammed Zain Elabdeen, a peer educator in the local police service, said he taught other policemen how to use condoms but did not provide them unless he was asked. "My role is awareness," he said. "If you just hand condoms out, it's like you're promoting sex."

The first step in most awareness-raising efforts is to approach local religious and tribal leaders. Without their endorsement, educational messages are unlikely to have any impact, said Musa Bungudu, country coordinator for UNAIDS in Sudan.

"The imams [Muslim religious leaders] have accepted to talk about HIV. They won't promote condoms, but they've agreed they can be promoted through the health system. It's not seen as appropriate for anyone outside the health system to distribute them," Bungudu said.

Local leaders are more likely to advocate marriage as an HIV-prevention strategy. Sex outside of marriage is prohibited in Islam, so simply encouraging religious fidelity is often considered an adequate response. "If people are committed to Islam, they'll prevent themselves from getting HIV," said Sheikh Faki Mohamed Alamin, one of the few imams in Kassala willing to talk about HIV.

But in this area, where poverty is widespread, the high cost of dowries and weddings makes marriage unaffordable for many young men. According to Ali Mohammedeen, who runs a network for local community-based organisations, such men are more likely to engage in "risky behaviour".

Awareness-raising efforts also have to take into account that women in eastern Sudan tend to stay close to home and rarely mingle with men in public. Indeed, to an outsider, the lack of women in the audience at the market is striking. Mubarak said the best strategy for reaching women with information about HIV and AIDS would be door-to-door campaigns.

The staff at GOAL have learned that even the design of awareness-raising posters has to take into account local attitudes to gender. "We had to change a poster that showed men and women mixed together because of feedback from the community," said Shealy. "Now the men are on one side and the women on the other. We call it the 'Kassala poster'."

Segregation of the sexes is even more pronounced in the rural areas of Kassala State. High levels of illiteracy and the need to develop educational materials in local languages add to the difficulty of talking about HIV in the countryside.

So far, awareness efforts have mainly been confined to urban areas. "You have to start somewhere, and urban populations are generally more at risk and easier to target than rural," said Shealy. "What needs to happen now is that [awareness-raising] needs to go beyond the urban peripheries."