Two of the four known groups of HIV strains that affect humans originated in western lowland gorillas in Africa, researchers from the University of Pennsylvania report in the March 2 edition of the peer-reviewed journal Proceedings of the National Academy of Sciences.
Dr. Beatrice Hahn, a professor of medicine and microbiology at Penn, and an international team of colleagues screened fecal samples from eastern lowland gorillas, western lowland gorillas, and mountain gorillas in Cameroon, Gabon, Uganda, and the Democratic Republic of Congo for signs of simian immunodeficiency virus (SIV) infection.
According to HealthyDay News, HIV (HIV-1) has four known groups: M, N, O and P. Previous studies found that groups M and N originated in chimpanzees in southern Cameroon, but the origins of groups O and P remained uncertain. Now, however, the scientists have found that the remaining two groups also originated in Cameroon, but in western lowland gorillas.
While all four subtypes of HIV can infect humans, only Group M was responsible for the AIDS epidemic that has killed millions of people worldwide, the researchers said. However, Group O has also infected a relatively large number of people (approximately 100,000) in Africa, while N and P have thus far only been identified in a handful of individuals in Cameroon.
In a statement, Dr. Hahn said that viral sequencing “revealed a high degree of genetic diversity among the different gorilla samples” and that two lineages of SIV were especially close to HIV groups O and P, indicating that those groups “originated in western lowland gorillas.”
“Understanding emerging disease origins is critical to gauge future human infection risks,” lead author Martine Peeters, a virologist from the Research and Development Institute (IRD) and the University of Montpellier in France, added.
She explained that “this study and others that our team has conducted in the past” had made it “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.”
Approximately 78 million people have been infected by HIV, a pathogen that can destroy a person’s immune cells and leave that individual’s body vulnerable to opportunistic diseases such as tuberculosis and pneumonia, since 1981, according to Discovery News. Based on UN statistics, nearly 40 million men and women have died as a result of the virus, the website added.
The study was funded by grants from the US National Institutes of Health (NIH), and scientists from the Perelman School of Medicine at the University of Pennsylvania, IRD, the University of Montpellier, the University of Edinburgh, and other institutions were involved in the research.
Last month, researchers from the Scripps Research Institute in Florida and colleagues from the US and France discovered a genetically-engineered protein that inactivates all known strains of HIV. The protein, they explained, mimics a pair of receptors on the surface of the immune cells that are ordinarily infected by the AIDS-causing pathogen.
When HIV encounters the protein, it starts behaving like it does when it infects a cell, which causes changes to occur in the virus that prevents it from any future attempts at infection. The protein was reportedly found to be effective against HIV-1, HIV-2 and a form of SIV.