The indigenous forest people of central Africa have been largely isolated from the rest of the world, but as they become more integrated into mainstream society the risk of sexual exploitation and HIV/AIDS is a growing threat.

Central Africa's pygmy populations, numbering a total of 300,000 to 500,000 people, have lived as hunter-gatherers in the forests of Burundi, Cameroon, the Democratic Republic of Congo (DRC), and the Republic of Congo (ROC) since time immemorial.

But the gradual encroachment of logging, farming and infrastructure projects, and the creation of protected areas, has forced them to abandon their traditional way of living and join the formal economy, working as casual labourers or on commercial farms.

This shift has brought them into closer contact with neighbouring ethnic communities whose HIV levels are generally higher. "Pygmy people must be seriously sensitised about HIV/AIDS," Sorel Eta, an ethnologist and researcher from ROC, told delegates at a recent conference in Impfondo, 800km north of the ROC capital, Brazzaville.

Studies in Cameroon and ROC in the 1980s and 1990s showed a lower prevalence of HIV in pygmy populations than among neighbouring ones, but recent increases have been recorded. One study found that the HIV prevalence among the Baka pygmies in eastern Cameroon went from 0.7 percent in 1993 to 4 percent in 2003.

Speakers at the conference noted that impoverished Twa pygmy women of communities in Burundi, DRC, Rwanda and elsewhere were turning to commercial sex work to make ends meet, but ignorance about the pandemic meant many were unaware of the dangers of unprotected sex.

"Almost all indigenous women in Burundi are illiterate ... ignorant of the fact that HIV/AIDS can also attack them," said Léonard Habimana, Burundi's first Twa journalist and the promoter of a private radio station, Radio Isanganiro, which educates people about the dangers of sexually transmitted infections, sexual violence and HIV/AIDS in pygmy communities.

"Because of poverty, sexual exploitation of indigenous women became a common fact," said Kapupu Diwa, head of a network of local and indigenous populations advocating for the sustainable management of forest ecosystems in central Africa. "It is in this environment that women sell sex for as little as US$0.20, or even biscuits."

Commercial sex work has also been bolstered by logging and infrastructure building, which often place large groups of transient labourers in camps set up in close proximity to pygmy communities.

A widely believed myth that sex with a Twa woman has the power to cleanse men of the HI virus places Twa women at additional risk. Human rights groups have also reported widespread sexual abuse of indigenous women in the conflict-ridden eastern DRC.

Despite these risks, pygmy populations generally have poor access to health services and information about HIV. In 2006, the British medical journal, The Lancet, published a study showing that the Twa consistently had worse access to healthcare than neighbouring communities.

According to the report, "Even where healthcare facilities exist, many people do not use them because they cannot pay for consultations and medicines, do not have the documents and identity cards needed to travel or obtain hospital treatment, or are subjected to humiliating and discriminatory treatment."