Chimpanzee-Killing Disease Linked by Researchers to New Species of Bacterium

A fatal disease has been killing chimpanzees at the Sierra Leone sanctuary for years and has been reported for the first time by an international team of researchers.

Led by researchers from the University of Wisconsin-Madison, the disease was reported on February 3rd in the journal Nature Communication.

The study suggests that the disease is caused by a newly discovered bacterium that comes as the world struggles with the onslaught of the COVID-19 pandemic.

Link Between Chimpanzee-Killing Disease and Newly Discovered Bacterium

Although the chimpanzee-killing disease has yet to be found in humans, the two species share roughly 99% of their DNA.

Tony Goldberg, a co-author of the study and a professor of epidemiology at the University of Wisconsin-Madison says, "There are very few pathogens that infect chimpanzees without infecting humans and very few pathogens that infect humans without infecting chimpanzees."

Other lethal diseases such as HIV and Ebola have jumped from great apes to humans. While other diseases like polio and influenza have gone through the opposite route.

Goldberg adds, "The staff at Tacaguma are super worried. It looks like something we need to be concerned about."

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Great Ape Health Mystery

A new species of bacterium in the Sarcina genus named, Sarcina troglodytae is associated with the deadly disease sweeping through the critically endangered Western chimpanzees (Pan trolodytes verus) in the Tacaguma sanctuary in Freetown, Sierra Leone.

The disease caused by the newly discovered bacterium has been named Epizootic Neurologic and Gastroecenteric Syndrome (ENGS). It causes neurological and gastrointestinal symptoms that have so far killed 56 chimps between 2005-2018.

Goldberg explains, "it was not subtle--the chimpanzees would stagger and stumble, vomit, and have diarrhea," He tells Science, "Sometimes they'd go to bed healthy and dead in the morning."

ENGS was first observed in 2005 where it suddenly struck its victims.

Chimpanzees that were healthy a day earlier begun to drunkenly stumble with a nervous system disorder known as ataxia. The great apes also suffered bloating of the stomach and intestines.

The chimpanzees appeared to be dying from gas that gets into the tissue of their intestines.

Sharon Deem, director of the Institue for Conservation Medicine at the Saint Louis Zoo says, "They did a very sound study. I think they did a great job on the epidemiology all the way up to the new genomic techniques."

Deem stressed that despite the work done it raises fascinating questions that require a tremendous amount of further studies. Whether the disease is caused by other factors adding to the bacterium or why there is a high prevalence of the disease in March, are questions researchers hope to answer.

Great apes including chimpanzees, western gorillas, orangutans, and bonobos are either endangered or critically endangered. Over the years, they have been losing much of their habitat due to human activities which is why scientists are working double-time to further understand the disease and get to the bottom of things.

Check out more news and information on Endangered Animals on Science Times.