Finding Virus in Wild Chimp Advances Hunt for Source of AIDS

Researchers hunting for the origin of AIDS have for the first time found an HIV-like virus in a chimpanzee in the wild -- but in a different part of Africa than they had expected. Scientists have long known that non-human primates carry their own version of HIV, but it has been found only in captive chimps.

The finding was puzzling because only one animal out of 58 tested had an HIV-like virus, and that animal had a virus that was genetically distant from the virus that infects humans. This indicates that this type of chimp in Tanzania could not be the source for human AIDS.

An important result of the research is a method to test animals in the wild without major disturbance of them. Scientists are tracking different chimps in a more remote part of Africa, where the virus is thought to have jumped from animals to humans. No one knows how prevalent or geographically or genetically diverse the virus is in chimps in the wild.

Scientists suspect that HIV originates from SIVcpz, a strain of simian immunodeficiency virus found in a subspecies of chimpanzee in west-central Africa. Hoping to bolster that theory, University of Alabama at Birmingham researcher Dr. Beatrice Hahn and her team developed a test to check urine and fecal samples for antibodies against SIV, and they learned to cull SIV genetic material from fecal samples. Of 58 animals tested, one had SIVcpz -- a healthy 23-year-old male in Tanzania. That is farther east than tests on captive chimps had led scientists to suspect the virus extended. The animal's strain was so genetically different that it ruled out east African chimps as the source of HIV, Hahn said.

Dr. Anthony S. Fauci, leading AIDS expert at the National Institutes of Health, said Hahn's team had developed a good way to study the evolution of the virus in this species "without invading or disturbing ecologically. It's part of the big picture of really tracking down the origin," said Fauci. The study is published in today's issue of Science (Vol. 295; No. 5554).

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