Viruses similar to HIV in humans were present in non-human primates in Africa at least 5 million years ago, according to a new study.
It is considered by most scientists, Medical Xpress indicates, that HIV-1, the virus responsible for AIDS, infiltrated the human population in the early 20th century following multiple transmissions of a similar chimpanzee virus known as SIVcpz.
According to the research brief, scientists now think that the age of HIV-like viruses, called lentiviruses, date back millions of years. The scientists have calculated this by tracking the changes in a host immunity gene called APOBEC3G. This gene was induced by ancient viral challenges.
The researcher found that a gene in lentiviruses that defends them against APOBEC3G has been evolving in tandem with the immune system gene. This finding enabled them to determine how long lentiviruses have been present in primates. The answer was that the association between primates and lentiviruses is estimated to be around 5 or 6 million years ago.
The finding suggests that HIV-like infections in primates are much older than previously thought.
The study has been published in the journal PLOS Pathogens by scientists at Fred Hutchinson Cancer Research Center.