From the Research
Yes, HIV originated from Simian Immunodeficiency Virus (SIV) in non-human primates, specifically from chimpanzees and sooty mangabey monkeys. The most recent and highest quality study, 1, published in 2013, provides strong evidence that SIVs from chimpanzees and gorillas from West Central Africa have crossed the species barrier on at least four occasions leading to HIV-1 in humans, while HIV-2 viruses result from at least eight to nine independent transmissions of SIVs infecting sooty mangabeys from West Africa.
Key Points:
- HIV-1, the most common type of HIV worldwide, evolved from SIV found in chimpanzees, as supported by studies such as 2 and 3.
- HIV-2, which is less common and primarily found in West Africa, originated from SIV in sooty mangabey monkeys, as reported in 4 and 5.
- The cross-species transmission likely occurred through human contact with infected primate blood during hunting or butchering activities, as suggested by 2 and 1.
- The virus adapted to the human host through genetic mutations that allowed it to effectively infect human cells and evade immune responses, as discussed in 3 and 1.
- Scientists have tracked these evolutionary changes through genetic analysis, showing that HIV-1 group M (responsible for the global AIDS pandemic) likely jumped to humans in the early 20th century in central Africa, as established by 5 and 1.
Implications:
- This zoonotic transmission represents a classic example of how pathogens can cross species barriers and adapt to new hosts, particularly when human activities increase exposure to wildlife, as highlighted by 2, 3, and 1.
- The genetic diversity of HIV-1 continues to increase over time due to co- or superinfections, and the expanded access to antiretrovirals leads to an increasing number of drug-resistant strains, especially in resource-limited countries, as noted in 1.