References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
HIV didn’t appear out of nowhere. The virus evolved from a closely related virus — simian immunodeficiency virus (SIV) — that naturally infects certain primates in Central and West Africa. Through a process called zoonotic transfer, SIV crossed from primates to humans and adapted into what we now know as HIV. Understanding this history helps put the pandemic in context.
Here’s what scientists have pieced together.
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Two Types of HIV
| Type | Origin | Global Impact |
|---|---|---|
| HIV-1 | Chimpanzees (Pan troglodytes troglodytes) in Central Africa | Responsible for the global pandemic — over 95% of infections worldwide |
| HIV-2 | Sooty mangabey monkeys in West Africa | Mainly confined to West Africa, less transmissible, slower progression |
How Did the Jump Happen?
The most widely accepted theory is that SIV entered humans through hunting, butchering and eating bushmeat. Blood-to-blood contact during these activities allowed the virus to cross the species barrier. Once in humans, SIV mutated and adapted to become HIV.
Genetic analysis suggests the jump happened multiple times, but the strain that became HIV-1 group M — the one responsible for the global pandemic — likely crossed to humans in the early 1900s, probably in what is now the Democratic Republic of Congo.
How HIV Spread
- Colonial-era urbanisation — growing cities like Kinshasa (then Léopoldville) created conditions for sexual networks and medical practices (unsterilised needles) that helped the virus spread
- Transport links — railways and river trade routes carried the virus to new areas
- International travel — HIV reached Haiti by the 1960s and the United States by the 1970s
- The virus was spreading silently for decades before it was recognised in 1981
When Was HIV First Recognised?
- 1981 — unusual clusters of Pneumocystis pneumonia and Kaposi’s sarcoma in young gay men in the US prompted the first reports
- 1983 — the virus was isolated by Luc Montagnier and Françoise Barré-Sinoussi in France
- 1984 — Robert Gallo’s team confirmed the virus as the cause of AIDS
- 1985 — the first HIV antibody test became available
- 1996 — combination antiretroviral therapy transformed HIV from fatal to manageable
Why It Matters Today
Understanding HIV’s origin helps scientists:
- Track how the virus evolves and diversifies
- Develop better vaccines and treatments
- Prepare for future zoonotic pandemics
- Combat misinformation and conspiracy theories about HIV’s origin
Read more: HIV-1 subtypes | HIV vaccine research | What is HIV?
Frequently Asked Questions
Was HIV created in a laboratory?
No. Extensive genetic evidence shows HIV evolved naturally from SIV in primates. The laboratory origin theory has been thoroughly investigated and rejected by the scientific community.
Can you get HIV from animals?
Not from contact with pets or farm animals. The original crossover events happened through direct blood contact during primate hunting in Africa, likely over a century ago.
Why hasn’t SIV made primates sick?
Most primate species that carry SIV have co-evolved with the virus over millions of years and don’t develop AIDS-like illness. Humans haven’t had time to develop this tolerance.
Related reading
- A to Z of Sex: Sexual Health Terms Explained
- Alcohol and HIV: What You Need to Know
- Anxiety and HIV: Coping and Getting Support
- Are All STIs Curable?
- Blood Problems and HIV: Anaemia, Low Platelets and More
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
