RESEACHERS who analysed wild chimp droppings said on Thursday that HIV originated in wild apes in Cameroon and then spread in humans across Africa and eventually the world.
The study, published in the journal Science, supports other studies that suggest that people caught the deadly human immunodeficiency virus from chimpanzees, perhaps by eating them.
The study says like many new infections, HIV appears to have been passed onto humans from animals they slaughtered. Chimpanzees are a delicacy and are widely eaten in most countries in West Africa.
Beatrice Hahn of the University of Alabama, USA, who led the study said, “The chimpanzee group that gave rise to HIV.....this chimp community resides in Cameroon. But that doesn’t mean the epidemic originated there because it didn’t,” Hahn, who has been studying the genetic origin of HIV for years, said in a telephone interview.
“We actually know where the epidemic took off. The epidemic took off in Kinshasa and Brazzaville.”
Kinshasa is in the Democratic Republic of Congo, formerly Zaire and faces Brazzaville in Congo, across the Congo River.
Uganda’s first AIDS cases were identified in 1982 with a prevalence rate hitting 9% in 1988. Currently, there are 1.4m people estimated to be infected with HIV. Of these, 170,000 are in urgent need of anti-retroviral drugs (ARVs).
Dr. Sam Okware, a commissioner in the ministry of health, said the chimp story was not new. “That is an old story. Since the identification of HIV, that story has been around,” Okware said.
Studies have traced HIV to a man who gave a blood sample in 1959 in Kinshasa, then called Leopoldville. Later analysis found the virus that leads to AIDS.
In people, HIV leads to AIDS but chimps get a version called simian immune deficiency virus (SIV) that causes them no harm. Humans are the only animals naturally susceptible to HIV.
AIDS was only identified 25 years ago. The virus now infects 40 million people around the world and has killed 25 million. Spread via blood, sexual contact and from mother to child during birth or breast-feeding, HIV has no cure and there is no vaccine, although drug cocktails can help control it.
SIV has been found in captive chimps but Hahn wanted to show it could be found in the wild, too.
Her team got the cooperation of the government of Cameroon and they hired skilled trackers.
“The chimps in that area are hunted. It’s certainly impossible to see them. It is hard to track them and find these materials,” Hahn said.
But the trackers managed to collect 599 samples of droppings.
Hahn’s laboratory found the DNA, identified each individual chimp and found evidence of the virus.
“We went to 10 field sites and we found evidence of infection in five. We were able to identify a total of 16 infected chimps and we were able to get viral sequences from all of them,” Hahn said.
The reasercher said up to 35% of the apes in some communities were infected. Not only that, they had different varieties, called clades, of the virus.