It is now 25 years since the HIV virus was discovered. The source of this virus, believed to be the African jungles has remained a mystery. But now an international team of researchers led by Beatrice Hahn of the University of Alabama at Birmingham has traced the virus to its natural reservoir in the wild chimps in jungles of south Cameroon. Their findings appear in the latest issue of the journal 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." But finding the source was dirty work since the researchers had to track the chimps and then collect 1,300 samples of their feces for genetic analysis. The study has been going on for a decade. It took them seven years to create a genetic tool that could help in the analysis.
Scientists have known from a long time that animals have a different version of HIV called SIV or simian immunodeficiency virus. However this is not that lethal in animals and does not cause immune disease in them. The main source was detected in the subspecies Pan troglodytes troglodytes.
There are three known types of HIV-1. Scientists think that as the virus transferred itself to humans probably from a chimp bite on a hunter, it changed its characteristic to a deadly form. The first human infected with HIV was a man from Kinshasa in Congo in 1959.
"It is likely that the jump between chimps and humans occurred in south-east Cameroon - and that virus then spread across the world," said Paul Sharp, professor of genetics at the University of Nottingham, who was also a part of the research team. "When you consider that HIV probably originated more than 75 years ago, it is most unlikely that there are any viruses out there that will prove to be more closely related to the human virus."
He added that the team was now working to understand the genetic differences "between SIVcpz and HIV-1 evolved as a response to the species jump."
