For decades, scientists have known that HIV-1, the virus responsible for the global AIDS pandemic, originally came from apes.
But what they didn’t know—until now—is that two of the four known strains of HIV-1 actually originated in gorillas, not chimpanzees.
A groundbreaking study from the University of Montpellier in France has uncovered that HIV-1 strains O and P were transmitted to humans from western lowland gorillas in Cameroon.
Previously, scientists had traced strains M and N back to chimpanzees, but the origins of the other two strains remained a mystery.
What does this discovery mean?
For one, it reinforces the idea that zoonotic diseases—viruses that jump from animals to humans—are a major threat to global health.
It also sheds light on how the consumption of bush meat may have played a role in HIV transmission.
But here’s the twist: not all HIV strains are created equal. While HIV-1 strain M has infected over 40 million people worldwide, causing the modern AIDS pandemic, strains O and P remain relatively rare.
This raises an important question: Why did one strain spread so aggressively, while the others remained localized?
The answer is more surprising than you might think.
How HIV Jumped from Gorillas to Humans
The discovery that gorillas played a role in HIV’s history was made possible through an extensive genetic study.
Researchers analyzed gorilla fecal samples from across Central Africa, looking for evidence of Simian Immunodeficiency Virus (SIV)—the primate version of HIV.
What they found was shocking:
- Western lowland gorillas (Gorilla gorilla gorilla) were carrying viruses genetically similar to HIV-1 strains O and P.
- These strains likely jumped to humans through direct contact with infected blood, possibly during the hunting, slaughter, or consumption of bush meat.
- Genetic analysis suggests that HIV-1 strain O may have first infected humans in the early 1900s, while strain P emerged later in the 20th century.
This means that HIV has been circulating among humans for well over a century—long before it was first identified in the 1980s.
But here’s where things get even more interesting.
Not All HIV Strains Spread Equally—Why?
If four different strains of HIV-1 made the jump to humans, why did only one of them—strain M—cause a global pandemic?
Let’s break it down:
- HIV-1 Strain M: The dominant strain, responsible for the AIDS crisis and the deaths of millions worldwide.
- HIV-1 Strain O: Circulates primarily in West and Central Africa, with around 100,000 known cases.
- HIV-1 Strains N and P: Extremely rare, with only a handful of reported cases.
At first glance, you might assume that strains O, N, and P were just weaker versions of the virus—less transmissible, less virulent. But according to researchers, that’s not the case.
“On this occasion, humans got lucky,” said Beatrice Hahn, a co-author of the study from the University of Pennsylvania.
The study found no clear genetic reason why strains O and P didn’t spread like strain M. In other words, these strains could have caused a global pandemic—but for some reason, they didn’t.
This raises a troubling question: What if the next zoonotic virus isn’t so contained?
Why Emerging Diseases Matter
Understanding the origins of HIV-1 isn’t just about filling in historical gaps—it’s about preparing for future pandemics.
Lead virologist Martine Peeters put it bluntly:
“Understanding emerging disease origins is critical to gauge future human infection risks.”
HIV isn’t the first deadly virus to jump from animals to humans, and it certainly won’t be the last. Recent history proves this:
- Ebola: Originated from fruit bats and infected humans through bush meat consumption.
- SARS and MERS: Both coronaviruses likely jumped from bats to other animals before infecting humans.
- COVID-19 (SARS-CoV-2): Thought to have originated in bats and possibly passed through pangolins or another intermediary host before infecting humans.
The pattern is clear: Zoonotic diseases pose one of the greatest threats to human health.
This is why researchers stress the importance of wildlife monitoring, stricter regulations on bush meat consumption, and improved disease surveillance in regions where human-animal interactions are common.
What Can We Learn from the HIV-Gorilla Connection?
The discovery that two HIV strains came from gorillas is more than just a scientific curiosity—it’s a wake-up call.
1. The Risk of Future Pandemics is Real
HIV, Ebola, and coronaviruses all originated in wild animals.
As deforestation, hunting, and human-wildlife interactions increase, so does the risk of new deadly viruses emerging.
2. Human Behavior Plays a Key Role
The bush meat trade—where wild animals are hunted, sold, and consumed—has been linked to multiple disease outbreaks.
While bush meat is a vital food source in some regions, safer practices and regulations could reduce the risk of zoonotic spillover.
3. Some Viruses Are Just More Dangerous Than Others
HIV-1 strain M spread worldwide, while strains O, N, and P remained contained.
The same pattern was seen with COVID-19, where one variant became dominant while others faded away.
This unpredictability makes early detection and rapid response critical.
What’s Next in the Fight Against Zoonotic Diseases?
The story of HIV’s origins in gorillas and chimpanzees is a reminder that viruses don’t respect species boundaries.
Today, researchers are still working to understand why some viruses jump to humans and cause pandemics, while others remain relatively contained.
The more we learn about diseases like HIV, the better we can prepare for the next outbreak—because it’s not a matter of if, but when.
As humans continue to push deeper into wildlife habitats, the risk of new, deadly viruses crossing over will only increase.
Our best defense?
Science, surveillance, and smarter policies to prevent the next pandemic before it begins.
Sources:
- Proceedings of the National Academy of Sciences
- University of Montpellier Study
- Reuters Interview with Beatrice Hahn
- World Health Organization Reports on HIV and Zoonotic Diseases
