Biologists and environmentalists warn that the growing appetite for 'bushmeat' in Africa is not only threatening Africa's great apes with extinction, it is also spreading AIDS to humans.

As logging companies forge roads into areas previously inaccessible to humans, apes are forced out of their habitats and then pursued by a growing numbers of hunters and butchers. In the marketplaces of Central Africa, it is a common sight to see the body parts of gorillas, bonobos and chimpanzees hanging on hooks to be sold as food.

The result is a sudden explosion in scope and impact of the traditional consumption of wild animal meat from a means of subsistence to an enormous and unsustainable business with global health implications, said American evolutionary biologist Dale Peterson.

"It's a US$361 million business, and the supply is collapsing based on sophisticated hunting techniques," said Peterson, the author of a book on the subject, Eating Apes.

Comparing the business to the US$1 billion dollar a year logging business which is expanding, he said that while the dwindling ape population remains a major concern to environmentalists, there were human health risks too. The butchering process of the apes is at the heart of the potential health crisis.

"We're eating our closest relatives," said Michael Dee, general curator at the Los Angeles Zoo. "If a person has a wound or gets blood in his mouth, then the disease would be transmitted." About 1% of HIV-2 cases - the type that affects West Africa - is transmitted during the butchering process of monkeys," he said.

Since diseases find ways to mutate or cross over to different species - including HIV and Severe Acute Respiratory Distress Syndrome (SARS), which is thought to have originated in Civet cats - the rise of a third strain of HIV is becoming increasingly likely as the bushmeat phenomenon grows, Dee said.

Only about 120,000 gorillas - enough to fill just one large football stadium - remain in the world, as well as 250,000 chimpanzees and 50,000 bonobos. By comparison, the number of humans is increasing at the rate of two stadiums a day, and expanding into new areas. "We owe it to them to save them," Peterson said.

But while 'orphanages' have sprung up to care for apes that have lost their parents to hunters' bullets, conservationists are having trouble making their warnings about the surge in appetite for bushmeat heard because the subject matter was too confronting for many.

"Not a lot of people want to buy a book of a gorilla's head in a pan or a hand being butchered," Peterson said. He and a coalition of defenders of Africa's besieged great apes are trying to rally public awareness and financial support for a drive to clamp down on the eating of apes.

A group of musicians in Los Angeles has joined the battle, producing a compact disc of world beat music to raise money for the cause.