Scientists discovered how monkeypox spread from fire-footed rope squirrels to a group of wild primates called sooty mangabeys in Côte d’Ivoire, Africa. By studying dead animals and analyzing what the primates ate, researchers found nearly identical virus samples in both species, proving for the first time that the virus can jump directly from squirrels to primates. This discovery is important because both squirrels and primates are hunted and eaten by people in West and Central Africa, suggesting monkeypox could potentially spread to humans through contact with infected animals.

The Quick Take

  • What they studied: How monkeypox virus spread from wild squirrels to a group of primates, and what this means for human health
  • Who participated: One group of wild sooty mangabeys (a type of primate) in a national park in Côte d’Ivoire, plus dead squirrels and other animals found in the same region
  • Key finding: Researchers found a dead squirrel infected with monkeypox just 3 kilometers away and 12 weeks before the primates got sick. The virus in the squirrel and primates was nearly identical, proving the squirrel was the source of the outbreak that sickened one-third of the primate group and killed four babies.
  • What it means for you: This shows that monkeypox can spread from wild animals to other animals, and potentially to humans who hunt, handle, or eat these animals. If you live in or travel to West or Central Africa, avoid contact with wild squirrels and primates, and be cautious about eating bushmeat from unknown sources.

The Research Details

Researchers investigated an outbreak of monkeypox in wild primates by collecting and testing dead animals from the area where the primates lived. They found a dead squirrel infected with the virus and compared its genetic material to the virus found in the sick primates. They also examined what the primates had eaten by analyzing their droppings (fecal samples) and reviewed video footage from 2014 showing the primates eating squirrels of the same species.

This detective-work approach allowed scientists to trace the outbreak back to its source. By finding nearly identical virus samples in both the squirrel and the primates, they could prove that the squirrel was the original source of infection. The timing also matched—the squirrel was found dead about 12 weeks before the primates got sick, which fits with how long it takes for the virus to spread and cause symptoms.

This type of investigation is valuable because it provides direct evidence of how viruses jump between different animal species in nature, something that’s rarely documented in the wild.

Understanding how viruses spread between wild animals is crucial for predicting and preventing outbreaks in humans. Most new diseases that infect people actually come from animals first. By studying real-world examples of animal-to-animal transmission, scientists can better understand the risks and develop strategies to protect human health.

This research was published in Nature, one of the world’s most respected scientific journals, which means it went through rigorous review. The evidence is strong because researchers found the actual infected animal, compared the genetic material directly, and had multiple types of evidence (dead animal, virus genetics, what the primates ate, and video footage). However, this is a single outbreak in one location, so the findings may not apply everywhere.

What the Results Show

The outbreak affected approximately one-third of a wild mangabey group, with four infant primates dying from the infection. Researchers identified a fire-footed rope squirrel found dead 3 kilometers away from the mangabey territory that was infected with monkeypox. The virus genetic material from the squirrel and the mangabeys was nearly identical, indicating they came from the same source.

Evidence of the transmission pathway came from multiple sources. Video footage from 2014 showed mangabeys from this same group eating fire-footed rope squirrels. When researchers analyzed the mangabeys’ droppings collected before the outbreak, they found squirrel DNA in two samples. Importantly, one of these samples also tested positive for monkeypox virus, suggesting the primates had eaten an infected squirrel.

The timing of events supports the squirrel-to-primate transmission theory. The dead squirrel was found approximately 12 weeks before the outbreak appeared in the mangabey group, which aligns with the expected incubation period for the virus. This represents the first documented case of direct detection of monkeypox transmission from rodents to primates in nature.

The research highlights that fire-footed rope squirrels can carry monkeypox virus and may serve as a natural reservoir (a population where the virus persists). The fact that the virus spread to multiple animals in the primate group suggests it can transmit between primates once introduced. The death of infant primates indicates the virus can cause severe disease in these animals.

Previous research suspected that African rodents, particularly squirrels, were involved in monkeypox emergence, but this is the first study to provide direct evidence of transmission from squirrels to primates. Earlier studies could only show that squirrels carried the virus or that primates had been exposed, but couldn’t prove the actual transmission event. This research fills that gap by documenting a real outbreak and tracing it back to its source.

This study documents a single outbreak in one location (Taï National Park in Côte d’Ivoire), so the findings may not apply to all regions of Africa or all squirrel and primate populations. The exact mechanism of transmission (whether through bites, scratches, or eating infected animals) isn’t completely clear, though eating appears likely. The study doesn’t provide information about how often this type of transmission occurs or how many people might be at risk. Additionally, the sample size of affected animals is relatively small, though the evidence is compelling.

The Bottom Line

People in West and Central Africa should minimize direct contact with wild squirrels and primates, including avoiding hunting, handling, or consuming these animals without proper protective equipment and food safety practices. If you must handle these animals, wear gloves and wash hands thoroughly afterward. Cook all bushmeat thoroughly to kill any viruses. Healthcare workers in affected regions should be alert for monkeypox symptoms in patients with recent animal exposure. (Confidence: Moderate to High—based on documented transmission pathway)

This research is most relevant to people living in or traveling to West and Central Africa, particularly those who hunt or consume wild animals. Healthcare providers in these regions should be aware of the transmission risk. Public health officials should consider this when developing disease surveillance and prevention strategies. People in other parts of the world should be aware of this risk when traveling to affected regions.

The outbreak in primates occurred approximately 12 weeks after exposure to the infected squirrel, suggesting this is the typical timeframe for symptoms to develop. However, individual cases may vary. Prevention through avoiding contact with infected animals is immediate and ongoing.

Want to Apply This Research?

  • If you live in or travel to affected regions, track any contact with wild animals (squirrels, primates, or other wildlife) with dates and locations. Note any symptoms like rash, fever, or swollen lymph nodes that appear within 2-4 weeks of animal contact.
  • Use the app to set reminders to avoid hunting or handling wild squirrels and primates. Create a checklist for safe food preparation practices if consuming bushmeat (wear gloves, cook thoroughly, wash hands). Log any potential exposures and monitor for symptoms.
  • Establish a 4-week monitoring period after any wild animal contact. Track body temperature, skin condition, and any unusual symptoms daily. If symptoms appear, immediately seek medical attention and report the animal contact to healthcare providers.

This research describes transmission of monkeypox between wild animals and does not provide medical advice for treating monkeypox in humans. If you believe you have been exposed to monkeypox or are experiencing symptoms such as rash, fever, or swollen lymph nodes, contact a healthcare provider immediately. This information is for educational purposes and should not replace professional medical diagnosis or treatment. The findings apply specifically to wildlife in West and Central Africa and may not reflect transmission patterns in other regions. Always consult with qualified healthcare professionals regarding personal health concerns.