Scientists have traced two of four strains of the deadly HIV virus to gorillas in Cameroon, MSN reports.
HIV (HIV-1) has at least four strains known as Groups M, N, O and P with each one having its own origin ranging from ape to man. But while M and N were known to have come from chimpanzees in Cameroon, the origin of the O and P strains remained unknown - till now.
HIV-1's Group M is the most widely spread, behind the greatest part of the epidemic with more than 40 million people now infected around the world.
Group P has only been detected in two people so far, while Group O has been found in central and western Africa, infecting about 100,000.
The breakthrough was made possible thanks to genetic samples from chimpanzees and gorillas from Cameroon, Gabon, Uganda and the Democratic Republic of Congo in a study led by Martine Peeters, a virologist at France's Research and Development Institute (IRD) and the University of Montpellier.
The team of scientists who worked on the research were however from the Perelman School of Medicine at the University of Pennsylvania, the University of Montpellier, the University of Edinburgh, and other institutions.
Speaking on the development, Peeters said:
"From this study and others that our team has conducted in the past it has become clear that both chimpanzees and gorillas harbor viruses that are capable of crossing the species barrier to humans and have the potential to cause major disease outbreaks. Understanding emerging disease origins is critical to gauge future human infection risks"
About 78 million people have been infected by HIV since 1981 while the United Nations estimates that 39 million have died from it.