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Durban - Chimpanzees may hold vital clues for mankind's war against the AIDS virus, but the apes could be wiped out before they reveal their secrets, a leading genetic expert warned on Wednesday.
Paul Sharp of Britain's University of Nottingham told an AIDS conference in Durban that the latest research indicated that chimpanzees - humanity's closest living relative - were an important but increasingly endangered resource for scientists hoping to better understand the HIV virus.
Chimpanzee populations are infected with viruses which closely resemble the HIV-1 strain of the AIDS virus which is most common among humans. Unlike humans, however, chimps do not progress to full-blown AIDS, an intriguing mystery for researchers who hope to discover how to slow or stop the deadly disease in humans.
"If we can understand chimpanzees maybe we can understand more about how the virus affects humans," Sharp said. "Of course, we need to do that before chimpanzees become extinct."
Some researchers fear Africa's chimpanzees could be wiped out in about 50 years - even earlier for certain species - because they are hunted for meat and threatened by deforestation and disease.
Forest Home Vanishing
One U.N. study last year said that less than 10 percent of the forest home of Africa's great apes will be left relatively undisturbed by 2030 if road building, construction of mining camps and other developments continue at current levels.
Sharp said researchers believed that chimpanzees originally contracted their version of the HIV virus - known as SIV - from other monkeys and that, at least initially, they likely suffered from AIDS-like symptoms which may have caused death.
He said it was now believed that either the virus evolved to become less deadly, a scenario he described as unlikely given the long incubation period, or that chimpanzees themselves developed physical strategies for disarming the virus or holding off its impact on their immune systems.
He said this natural coping mechanism may already be starting in some human populations, noting that studies have found isolated but as-yet unexplained instances of individuals where HIV infection does not progress at the same rate as seen in broader samples.
But in order to understand the process more fully, and perhaps find ways to accelerate it, it will be necessary to get a clearer picture of what happens with SIV-infected chimpanzees, he said.
"It gives obvious clues to how you can treat people successfully," he said.
Sharp added that the latest research on the genetic history of the HIV virus confirmed that it most likely first spread to humans in West Africa - possibly in Cameroon - as early as the 1930s, although initial cases were so rare that it took decades to establish the true threat posed by the disease.
The virus likely got its first major beachhead in a human population, what viral scientists term the "founder event," some decades later as it arrived in a major urban area, most likely teeming Kinshasa in Democratic Republic of Congo, he said.
But research into HIV history also reveals the astonishing complexity of the virus and its ability to mutate and recombine with other strains - continually producing "new and improved" versions that outpace mankind's efforts at treatment, he said.
"What we know about how the virus evolves is not very good news for therapies and vaccines ... it is going to be very difficult," Sharp said.
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