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.