AIDS ancestry traced to chimps.

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An HIV trail from the wild AIDS ancestry traced to chimps http://www.hindu.com/2006/05/26/stories/2006052601192000.htm WASHINGTON: Twenty-five years after the first cases of Acquired Immune Deficiency Syndrome, or AIDS, emerged, scientists have confirmed that the human immunodeficiency virus, or HIV, plaguing humans really did originate in wild chimpanzees, in a corner of Cameroon. Solving the mystery of HIV's ancestry was dirty work. Scientists employed trackers to plunge through dense jungle and collect the fresh faeces of wild apes — more than 1,300 samples. Before that, it took seven years just to develop the testing methods to genetically trace the primate version of the virus in living wild chimps without hurting endangered species. The tools Until now, "no one was able to look. No one had the tools," said Beatrice Hahn of the University of Alabama at Birmingham. She led the team of international researchers that reported this in Friday's edition of Science. "We're 25 years into this pandemic," Dr. Hahn said. "We don't have a cure. We don't have a vaccine. But we know where it came from. At least we can make a check mark on one of those." Scientists long have known that nonhuman primates carry their own version of the AIDS virus,

called SIV or simian immunodeficiency virus. But with one exception, it had been found only in captive chimpanzees, particularly a subspecies that populates mostly West Africa. It was not known how prevalent the virus was in chimps in the wild, or how genetically or geographically diverse it was, complicating efforts to pin down the jump from animal to man. Dr. Hahn's team tested chimp faeces for SIV antibodies, finding them in a subspecies called Pan troglodytes troglodytes in southern Cameroon. Chimps tend to form geographically distinct communities. By genetically analysing the faeces, researchers could trace individual infected chimps. The team found some chimp communities with infection rates as high as 35 percent, while others had no infection at all. Every single infected chimp had a common base genetic pattern that

indicated a common ancestor, Dr. Hahn said. There are three types of HIV-1, the strain of the human virus responsible for most of the worldwide epidemic. Genetic analysis let Hahn identify chimp communities near Cameroon's Sanaga river whose viral strains are most closely related to the most common of those HIV-1 subtypes. "The genetic similarity was striking," Dr. Hahn said. The first one The first human known to be infected with HIV was a man from Kinshasa in the nearby country of Congo who had his blood stored in 1959 as part of a medical study, decades before scientists knew the AIDS virus existed. Presumably, someone in rural Cameroon was bitten by a chimp or was cut while butchering one and became infected with the ape virus. That

person passed it to someone else. (!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! - Jagannath) The Sanaga long has been a commercial waterway, for transporting hardwood, ivory and other items to more urban areas. Eventually, someone infected made it to Kinshasa. — AP "Our ideal is not the spirituality that withdraws from life but the conquest of life by the power of the spirit." - Aurobindo.

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